Underwriting Agreement

EXHIBIT 1.1

ALLIS-CHALMERS ENERGY INC.

Common Stock

UNDERWRITING AGREEMENT

dated January 23, 2007

Underwriting Agreement

January 23, 2007

RBC Capital Markets Corporation
As Representative of the several Underwriters
Listed in Schedule A hereto c/o

RBC Capital Markets Corporation
One Liberty Plaza
New York, New York 10006

Ladies and Gentlemen:

     Introductory. Allis-Chalmers Energy Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A hereto (the “Underwriters”) an aggregate of 6,000,000 shares (the “Firm Shares”) of its Common Stock, par value $0.01 per share (the “Common Stock”). In addition, the Company has granted to the Underwriters an option to purchase up to an additional 900,000 shares (the “Optional Shares”) of Common Stock, as provided in Section 2. The Firm Shares and, if and to the extent such option is exercised, the Optional Shares, are collectively called the “Shares”. RBC Capital Markets Corporation has agreed to act as representative of the several Underwriters (in such capacity, the “Representative”) in connection with the offering and sale of the Shares.

     As more fully described in the Registration Statement (as defined below), the Company purchased substantially all of the assets of Oil & Gas Rental Services, Inc. (“Oil & Gas Rental”) on December 18, 2006. The purchase by the Company of substantially all of the assets of Oil & Gas Rental, as described in the Registration Statement, is referred to herein as the “Acquisition.” In connection with the Acquisition, the Company (a) received a limited waiver of certain provisions of Sections 2.04, 7.01 and 7.04 of the Company’s $25 million senior secured credit facility among the Company, each lender from time to time party thereto, and Royal Bank of Canada (the “Bank Credit Facility”) and (b) will (i) offer and sell the Shares contemplated by this Agreement and (ii) offer and sell the Company’s Senior Notes due 2017 (the “Notes”) pursuant to a purchase agreement dated January 24, 2007, among the Company, the guarantors and the initial purchasers named therein. The proceeds of this offering, together with the proceeds from the offering of the Notes, will be used to repay the debt outstanding under the Company’s $300 million bridge loan facility, which the Company incurred to finance the Acquisition. The aforementioned transactions are collectively referred to herein as the “Transactions.”

     Section 1. Representations and Warranties of the Company.

     The Company hereby represents and warrants to, and covenants with each Underwriter as follows:

     (a) Filing of the Registration Statement. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a registration statement on Form S-3 (File No. 333-139058), which contains a base prospectus (the “Base Prospectus”), to be used in connection with the public offering and sale of the Shares. Such Registration Statement, as amended, including the financial statements, exhibits and schedules thereto, and the documents incorporated by reference in the prospectus supplement and the Prospectus (as defined below) contained in the Registration Statement in the form in which it was declared effective by the Commission at each time of effectiveness under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including any required information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430B under the Securities Act or the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder (collectively, the “Exchange Act”), is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of the Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. Any preliminary prospectus supplement to the Base Prospectus that describes the Shares and the offering thereof and is used prior to filing of the Prospectus is called, together with the Base Prospectus, a “preliminary prospectus.” The term “Prospectus” shall mean the final prospectus relating to the Shares that is first filed pursuant to Rule 424(b) under the Securities Act after the date and time that this Agreement is executed and delivered by the parties hereto (the “Execution Time”). Any reference herein to the Registration Statement, any preliminary prospectus, the Disclosure Package (as defined herein) or the Prospectus shall be deemed to refer to and include the documents incorporated by reference therein pursuant to Item 12 of Form S-3 under the Securities Act; any reference to any amendment or supplement to any preliminary prospectus or the Prospectus shall be deemed to refer to and include any documents filed after the date of such preliminary prospectus or Prospectus, as the case may be, under the Exchange Act, and incorporated by reference in such preliminary prospectus or Prospectus, as the case may be; and any reference to any amendment to the Registration Statement shall be deemed to refer to and include any annual report of the Company filed pursuant to Section 13(a) or 15(d) of the Exchange Act after the effective date of the Registration Statement that is incorporated by reference in the Registration Statement.

     (b) Compliance with Registration Requirements. The Company meets the requirements for the use of Form S-3 under the Securities Act. The Registration Statement has been declared effective by the Commission under the Securities Act. The Company has complied to the Commission’s satisfaction with all requests of the Commission for additional or supplemental information. No stop order suspending the effectiveness of the Registration Statement is in effect, the Commission has not issued any order or notice preventing or suspending the use of the Registration Statement, any preliminary prospectus or the Prospectus

and no proceedings for such purpose have been instituted or are pending or, to the knowledge of the Company, are contemplated or threatened by the Commission.

     Each preliminary prospectus and the Prospectus when filed complied in all material respects with the Securities Act, and if filed by electronic transmission pursuant to EDGAR (except as may be permitted by Regulation S-T under the Securities Act), was identical in content to the copy thereof delivered to the Underwriters for use in connection with the offer and sale of the Shares, other than with respect to any artwork and graphics that were not filed. Each of the Registration Statement and any post-effective amendment thereto, at the time it became effective and at the date hereof, complied and will comply in all material respects with the Securities Act and did not and will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein not misleading. The Prospectus (including any Prospectus wrapper), as amended or supplemented, as of its date, at the time of any filing pursuant to Rule 424(b), at the Closing Date (as defined herein) and at any Subsequent Closing Date (as defined herein), did not and will not contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The representations and warranties set forth in the two immediately preceding sentences do not apply to statements in or omissions from the Registration Statement or any post-effective amendment thereto, or the Prospectus, or any amendments or supplements thereto, made in reliance upon and in conformity with information relating to any Underwriter furnished to the Company in writing by the Representative expressly for use therein, it being understood and agreed that the only such information furnished by the Representative consists of the information described as such in Section 8(b) hereof. There is no contract or other document required to be described in the Prospectus or to be filed as an exhibit to the Registration Statement that has not been described or filed as required.

     (c) Documents Incorporated by Reference. Except as set forth on Schedule F hereto, the documents incorporated by reference in the Prospectus, when they became effective or were filed with the Commission, as the case may be, conformed in all material respects to the requirements of the Exchange Act. Any further documents so filed and incorporated by reference in the Prospectus or any further amendment or supplement thereto, when such documents become effective or are filed with the Commission, as the case may be, will conform in all material respects to the requirements of the Exchange Act and the rules and regulations of the Commission thereunder.

     (d) Disclosure Package. The term “Disclosure Package” shall mean (i) the Base Prospectus, including any preliminary prospectus supplement, (ii) the issuer free writing prospectuses as defined in Rule 433 of the Securities Act prepared by or on behalf of the Company or used or referred to by the Company in connection with the offering of the Shares (each, an “Issuer Free Writing Prospectus”), if any, identified in Schedule B hereto, (iii) any other “free writing prospectus” (as defined in Rule 405 of the Securities Act) that the Representative and the Company shall hereafter expressly agree in writing to treat as part of the Disclosure Package, and (iv) Schedule C hereto, which indicates the number of Shares being sold and the price at which the Shares will be sold to the public in accordance with this Agreement and the estimated proceeds to the Company from the sale of the Shares. As of 6:00 p.m. (Eastern time) on the date of execution and delivery of this Agreement (the “Applicable Time”), the

Disclosure Package did not contain any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from the Disclosure Package based upon and in conformity with written information furnished to the Company by any Underwriter through the Representative specifically for use therein, it being understood and agreed that the only such information furnished by or on behalf of any Underwriter consists of the information described as such in Section 8(b) hereof.

     (e) Company Not Ineligible Issuer. (i) At the time of filing the Registration Statement and (ii) as of the date of the execution and delivery of this Agreement, the Company was not and is not an Ineligible Issuer (as defined in Rule 405 of the Securities Act), without taking account of any determination by the Commission pursuant to Rule 405 of the Securities Act that it is not necessary that the Company be considered an Ineligible Issuer.

     (f) Issuer Free Writing Prospectuses. Each Issuer Free Writing Prospectus, as of its issue date and at all subsequent times through the completion of the offering of Shares under this Agreement or until any earlier date that the Company notified or notifies the Representative as described in the next sentence, did not, does not and will not include any information that conflicted, conflicts or will conflict with the information contained in the Registration Statement. If at any time following issuance of an Issuer Free Writing Prospectus there occurred or occurs an event or development as a result of which such Issuer Free Writing Prospectus conflicted or would conflict with the information contained in the Registration Statement, the Company has promptly notified or will promptly notify the Representative and has promptly amended or supplemented or will promptly amend or supplement, at its own expense, such Issuer Free Writing Prospectus to eliminate or correct such conflict. The foregoing two sentences do not apply to statements in or omissions from any Issuer Free Writing Prospectus based upon and in conformity with written information furnished to the Company by any Underwriter through the Representative specifically for use therein, it being understood and agreed that the only such information furnished by any Underwriter consists of the information described as such in Section 8(b) hereof.

     (g) Accuracy of Statements in Prospectus. The statements in each of the preliminary prospectus and the Prospectus under the headings “Business—Legal Proceedings”, “Business— Federal Regulation and Environmental Matters”, “Description of Our Indebtedness” , “Certain U.S. Federal Income Tax Considerations for Non-U.S. Holders,” and “Description of Capital Stock”, insofar as such statements summarize legal matters, agreements, documents or proceedings discussed therein, are accurate and fair summaries of such legal matters, agreements, documents or proceedings.

     (h) Distribution of Offering Material by the Company. The Company has not distributed and will not distribute, prior to the later of the last Subsequent Closing Date (as defined below) and the completion of the Underwriters’ distribution of the Shares, any offering material in connection with the offering and sale of the Shares other than a preliminary prospectus, the Prospectus, any Issuer Free Writing Prospectus reviewed and consented to by the Representative or included in Schedule B hereto or the Registration Statement.

     (i) The Underwriting Agreement. This Agreement has been duly authorized, executed and delivered by, and is a valid and binding agreement of the Company, enforceable against the Company in accordance with its terms, except as rights to indemnification hereunder may be limited by applicable law and except as the enforcement hereof may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or affecting the rights and remedies of creditors or by general equitable principles.

     (j) Authorization of the Transactions. The Company has or will have on or prior to the Closing Date all requisite power and authority to consummate the Transactions to which it is a party and to enter into all agreements related to the Transactions (collectively, the “Transaction Documents”) to which it is a party. Each of the Transaction Documents has been or will have been on or prior to the Closing Date, duly authorized by the Company and, when executed and delivered by the Company (assuming due authorization, execution and delivery by the other parties thereto) constitute a legal, valid and binding agreement of the Company, enforceable against the Company, in accordance with its terms, except as such enforcement thereof may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or affecting the rights and remedies of creditors generally or by general equitable principles.

     (k) Authorization of the Shares. The Shares to be purchased by the Underwriters from the Company have been duly authorized for issuance and sale pursuant to this Agreement and, when issued and delivered by the Company to the Underwriters pursuant to this Agreement on the Closing Date or any Subsequent Closing Date, will be validly issued, fully paid and nonassessable.

     (l) No Transfer Taxes. There are no transfer taxes or other similar fees or charges under federal law or the laws of any state, or any political subdivision thereof, required to be paid in connection with the execution and delivery of this Agreement or the issuance by the Company or sale by the Company of the Shares.

     (m) No Applicable Registration or Other Similar Rights. There are no persons with registration or other similar rights to have any equity or debt securities registered for sale under the Registration Statement or included in the offering contemplated by this Agreement, except for such rights as have been duly waived.

     (n) No Material Adverse Change. Except as otherwise disclosed in the Disclosure Package and the Prospectus, subsequent to the respective dates as of which information is given in the Disclosure Package: (i) there has been no material adverse change, or any development that could reasonably be expected to result in a material adverse change, in the condition, financial or otherwise, or in the earnings, business or operations, whether or not arising from transactions in the ordinary course of business, of the Company and its subsidiaries listed on Annex A attached hereto (the “Subsidiaries”), considered as one entity (any such change is called a “Material Adverse Change”); (ii) the Company and its Subsidiaries, considered as one entity, have not incurred any material liability or obligation, indirect, direct or contingent, not in the ordinary course of business, nor entered into any material transaction or agreement not in the ordinary course of business; and (iii) there has been no dividend or distribution of any kind declared, paid or made by the Company or, except for dividends paid to the Company or other

Subsidiaries, any of its Subsidiaries on any class of capital stock or repurchase or redemption by the Company or any of its Subsidiaries of any class of capital stock.

     (o) Independent Accountants. Each of the accounting firms listed on Schedule E hereto, who have expressed their opinion with respect to the financial statements (which term as used in this Agreement includes the related notes thereto) and any supporting schedules thereto filed with the Commission as part of or incorporated by reference in the Registration Statement and included or incorporated by reference in the Disclosure Package and the Prospectus, are independent registered public accounting firms, in the case of UHY Mann Frankfort Stein & Lipp LLP, UHY LLP, and Gordon, Hughes and Banks, LLP, or an independent public accounting firm, in the case of Sibille (la firma argentina miembro de KPMG International, una cooperativa suiza), or independent certified public accountants, in the case of the other firms listed on Schedule E hereto, with respect to the Company as required by the Securities Act and the Exchange Act and the applicable published rules and regulations thereunder.

     (p) Preparation of the Financial Statements. The consolidated financial statements of the Company filed with the Commission as a part of or incorporated by reference in the Registration Statement and included or incorporated by reference in the Disclosure Package and the Prospectus present fairly the consolidated financial position of the Company and its Subsidiaries or of DLS, Specialty Rental Tools Inc., W.T. Enterprises Inc., Delta Rental Service, Inc., Capcoil Tubing Services, Inc. and Petro-Rentals, Incorporated (“Petro-Rentals”), as the case may be, as of and at the dates indicated and the results of their respective operations and cash flows for the periods specified. The supporting schedules included or incorporated by reference in the Registration Statement present fairly the information required to be stated therein. Such financial statements and any supporting schedules thereto comply as to form with the applicable accounting requirements of the Securities Act and have been prepared in conformity with generally accepted accounting principles, as applied in the United States, applied on a consistent basis throughout the periods involved, except as may be expressly stated in the related notes thereto. The Registration Statement contains all financial statements or supporting schedules that are required to be included or incorporated by reference therein. The financial data set forth in the preliminary prospectus and the Prospectus under the captions “Prospectus Supplement Summary—Summary Historical and Pro Forma Consolidated Financial Information” and “Capitalization” fairly present the information set forth therein on a basis consistent with that of the audited financial statements contained in the Registration Statement. The Company’s ratios of earnings to fixed charges incorporated into the Prospectus by reference to the Company’s Current Report on Form 8-K filed with the Commission on January 4, 2007 (including Exhibit 12.1 thereto) have been calculated in compliance with Item 503(d) of Regulation S-K under the Securities Act. The summary pro forma as adjusted consolidated statement of operations and other information of the Company and its Subsidiaries (including Petro-Rentals) and Oil & Gas Rental, and the related notes thereto included under the captions “Unaudited Pro Forma as Adjusted Consolidated Financial Information” and elsewhere in the preliminary prospectus and the Prospectus and in the Registration Statement or incorporated by reference in the preliminary prospectus, the Prospectus and the Registration Statement, present fairly the information contained therein, have been prepared in accordance with the Commission’s rules and guidelines with respect to pro forma financial statements and have been properly presented on the basis described therein, and the assumptions used in the preparation thereof are reasonable and the

adjustments used therein are appropriate to give effect to the transactions and circumstances referred to therein.

     (q) Incorporation and Good Standing of the Company and its Subsidiaries. Each of the Company and its Subsidiaries has been duly incorporated, formed or organized and is validly existing as a corporation, limited partnership or limited liability company in good standing under the laws of the jurisdiction of its incorporation, formation or organization and has corporate, limited liability or other organization power and authority to own, lease and operate its properties and to conduct its business as described in the Disclosure Package and the Prospectus and, in the case of the Company, to enter into and perform its obligations under this Agreement. Each of the Company and its Subsidiaries is duly qualified as a foreign corporation, limited partnership, limited liability company or other organization to transact business and is in good standing in each jurisdiction in which such qualification is required, whether by reason of the ownership or leasing of property or the conduct of business, except for such jurisdictions where the failure to so qualify or to be in good standing would not, individually or in the aggregate, result in a Material Adverse Change. Except as disclosed in the preliminary prospectus and the Prospectus, all of the issued and outstanding shares of capital stock or membership interests of each Subsidiary of the Company have been duly authorized and validly issued, are fully paid and nonassessable and are owned by the Company, directly or through one or more Subsidiaries, free and clear of any security interest, mortgage, pledge, lien, encumbrance or claim. The Company does not own or control, directly or indirectly, any corporation, association or other entity other than the Subsidiaries listed in Annex A hereto.

     (r) Capitalization and Other Capital Stock Matters. The authorized, issued and outstanding capital stock of the Company is as set forth in the Disclosure Package and the Prospectus under the caption “Capitalization” (other than for subsequent issuances, if any, pursuant to employee benefit plans described in the Disclosure Package and the Prospectus or upon exercise of outstanding options or warrants described in the Disclosure Package and the Prospectus, as the case may be). The Common Stock (including the Shares) conforms in all material respects to the description thereof contained in the Disclosure Package and the Prospectus. All of the issued and outstanding shares of Common Stock have been duly authorized and validly issued, are fully paid and nonassessable and have been issued in compliance with federal and state securities laws. None of the outstanding shares of Common Stock were issued in violation of any preemptive rights, rights of first refusal or other similar rights to subscribe for or purchase securities of the Company. There are no authorized or outstanding options, warrants, preemptive rights, rights of first refusal or other rights to purchase, or equity or debt securities convertible into or exchangeable or exercisable for, any capital stock of the Company or any of its Subsidiaries other than those accurately described in the Disclosure Package and the Prospectus. The description of the Company’s stock option, stock bonus and other stock plans or arrangements, and the options or other rights granted thereunder, set forth or incorporated by reference in the Disclosure Package and the Prospectus, accurately and fairly presents the information required to be shown with respect to such plans, arrangements, options and rights.

     (s) Listing. The Shares have been approved for listing on the American Stock Exchange, subject only to official notice of issuance.

     (t) Non-Contravention of Existing Instruments; No Further Authorizations or Approvals Required. Neither the Company nor any of its Subsidiaries is in violation of its charter, by-laws or equivalent organizational documents, or is in default (or, with the giving of notice or lapse of time, would be in default) (“Default”) under any indenture, mortgage, loan or credit agreement, note, contract, franchise, lease or other instrument to which the Company or any of its Subsidiaries is a party or by which it or any of them may be bound (including, without limitation, the concurrent Notes offering or the related indenture and the Bank Credit Facility) or to which any of the property or assets of the Company or any of its Subsidiaries is subject (each, an “Existing Instrument”), except for such Defaults as would not, individually or in the aggregate, result in a Material Adverse Change. The Company’s execution, delivery and performance of this Agreement and consummation of the transactions contemplated hereby, by the Disclosure Package and by the Prospectus (i) have been duly authorized by all necessary corporate action and will not result in any violation of the provisions of the charter, by-laws or equivalent organizational documents of the Company or any Subsidiary, (ii) will not conflict with or constitute a breach of, or Default or a Debt Repayment Triggering Event (as defined below) under, or result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its Subsidiaries pursuant to, or require the consent of any other party to, any Existing Instrument, except for such conflicts, breaches, Defaults, liens, charges or encumbrances as would not, individually or in the aggregate, result in a Material Adverse Change and (iii) will not result in any violation of any law, administrative regulation or administrative or court decree applicable to the Company or any Subsidiary, except for such violations as would not, individually or in the aggregate, result in a Material Adverse Change. No consent, approval, authorization or other order of, or registration or filing with, any court or other governmental or regulatory authority or agency, is required for the Company’s execution, delivery and performance of this Agreement and consummation of the transactions contemplated hereby, by the Disclosure Package and by the Prospectus, except such as have been obtained or made by the Company and are in full force and effect under the Securities Act, applicable state securities or blue sky laws and except such as may be required by federal and state securities laws or blue sky laws and from the National Association of Securities Dealers, Inc. (the “NASD”). As used herein, a “Debt Repayment Triggering Event” means any event or condition which gives, or with the giving of notice or lapse of time would give, the holder of any note, debenture or other evidence of indebtedness (or any person acting on such holder’s behalf) the right to require the repurchase, redemption or repayment of all or a portion of such indebtedness by the Company or any of its Subsidiaries.

     (u) No Material Actions or Proceedings. Except as disclosed in the Disclosure Package and the Prospectus, there are no legal or governmental actions, suits or proceedings pending or, to the Company’s knowledge, threatened (i) against or affecting the Company or any of its Subsidiaries or (ii) which has as the subject thereof any property owned or leased by, the Company or any of its Subsidiaries, where in any such case (A) it is reasonably expected that such action, suit or proceeding might be determined adversely to the Company or such Subsidiary and (B) any such action, suit or proceeding, if so determined adversely, would reasonably be expected to result in a Material Adverse Change or adversely affect the consummation of the transactions contemplated by this Agreement and by the Preliminary Prospectus and the Prospectus in the “Use of Proceeds” section. No labor dispute with the employees of the Company or any of its Subsidiaries exists or, to the best of the Company’s

knowledge, is threatened or imminent which, if determined adversely to the Company would reasonably be expected to result in a Material Adverse Change.

     (v) Intellectual Property Rights. The Company and its Subsidiaries own or possess sufficient trademarks, trade names, patent rights, copyrights, licenses, approvals, trade secrets and other similar rights (collectively, “Intellectual Property Rights”) reasonably necessary to conduct their businesses as described in the Preliminary Prospectus and the Prospectus; and the expected expiration of any of such Intellectual Property Rights if not renewed or replaced would not result in a Material Adverse Change. Neither the Company nor any of its Subsidiaries has received any notice of infringement or conflict with asserted Intellectual Property Rights of others, which infringement or conflict, if the subject of an unfavorable decision, would result in a Material Adverse Change.

     (w) All Necessary Permits, etc. Except as disclosed in the Disclosure Package and the Prospectus, the Company and each Subsidiary possess such valid and current certificates, authorizations or permits issued by the appropriate state, federal or foreign regulatory agencies or bodies necessary to conduct their respective businesses as currently conducted, and neither the Company nor any Subsidiary has received any notice of proceedings relating to the revocation or modification of, or non-compliance with, any such certificate, authorization or permit which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, could result in a Material Adverse Change.

     (x) Title to Properties. Except as disclosed in the Disclosure Package and the Prospectus, the Company and each of its Subsidiaries have good and marketable title to all the properties and assets reflected as owned in the financial statements referred to in Section 1(p) above (or elsewhere in the Disclosure Package and the Prospectus), in each case free and clear of any security interests, mortgages, liens, encumbrances, equities, claims and other defects, except (i) such as do not materially and adversely affect the value of such property and (ii) such as do not materially interfere with the current or currently proposed use of such property by the Company or such Subsidiary. The real property, improvements, equipment and personal property held under lease by the Company or any Subsidiary are held under valid and enforceable leases, with such exceptions as are not material and do not materially interfere with the current or currently proposed use of such real property, improvements, equipment or personal property by the Company or such Subsidiary.

     (y) Tax Law Compliance. The Company and its consolidated Subsidiaries have filed all necessary federal, state and foreign income and franchise tax returns and have paid all taxes required to be paid by any of them and, if due and payable, any related or similar assessment, fine or penalty levied against any of them, except, in all cases, for any such tax, assessment, fine or penalty that the Company is contesting in good faith and except, in any case, in which the failure to so file or pay would not in the aggregate result in a Material Adverse Change. The Company has made adequate charges, accruals and reserves in the applicable financial statements referred to in Section 1(p) above in respect of all federal, state and foreign income and franchise taxes for all periods as to which the tax liability of the Company or any of its consolidated Subsidiaries has not been finally determined, except where the failure to make such charges, accruals and reserves would not result in a Material Adverse Change.

     (z) Company not an “Investment Company”. The Company has been advised of the rules and requirements under the Investment Company Act of 1940, as amended (the “Investment Company Act”). The Company is not, and after receipt of payment for the Shares and the application of the proceeds thereof as contemplated under the caption “Use of Proceeds” in the preliminary prospectus and the Prospectus will not be, an “investment company” within the meaning of the Investment Company Act and the Company intends to conduct its business in a manner so that it will not become subject to the Investment Company Act.

     (aa) Insurance. Except as disclosed in the Disclosure Package and the Prospectus, each of the Company and its Subsidiaries are insured by recognized, financially sound institutions with policies in such amounts and with such deductibles and covering such risks as are generally deemed adequate and customary for their businesses including, but not limited to, policies covering real and personal property owned or leased by the Company and its Subsidiaries against theft, damage, destruction, acts of vandalism and earthquakes. Except as disclosed in the Disclosure Package or the Prospectus, the Company has no reason to believe that it or any Subsidiary will not be able (i) to renew its existing insurance coverage as and when such policies expire or (ii) to obtain comparable coverage from similar institutions as may be necessary or appropriate to conduct its business as now conducted and at a cost that would not result in a Material Adverse Change.

     (bb) Payment of Dividends by Subsidiaries. No Subsidiary of the Company is currently prohibited, directly or indirectly, from paying any dividends to the Company or any other Subsidiary, from making any other distribution on such Subsidiary’s capital stock, from repaying to the Company or any other Subsidiary any loans or advances to such Subsidiary from the Company or any other Subsidiary or from transferring any of such Subsidiary’s property or assets to the Company or any other Subsidiary of the Company, except as described in or contemplated in the Disclosure Package and the Prospectus.

     (cc) No Price Stabilization or Manipulation. The Company has not taken and will not take, directly or indirectly, any action designed to or that might be reasonably expected to cause or result in stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Shares. The Company acknowledges that the Underwriters may engage in passive market-making transactions in the Shares on the Nasdaq Stock Market, Inc. in accordance with Regulation M under the Exchange Act.

     (dd) Related Party Transactions. There are no business relationships or related-party transactions involving the Company or any Subsidiary or any other person required to be described in the preliminary prospectus or the Prospectus that have not been described as required.

     (ee) Internal Controls and Procedures. Except as disclosed in the Disclosure Package and the Prospectus, or in any document incorporated by reference therein, the Company maintains a system of accounting controls sufficient to provide reasonable assurance that (A) transactions are executed in accordance with management’s general or specific authorizations; (B) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles as applied in the United States and to maintain asset accountability; (C) access to assets is permitted only in accordance

with management’s general or specific authorization; and (D) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences.

     (ff) No Material Weakness in Internal Controls. Except as disclosed in the Disclosure Package and the Prospectus, or in any document incorporated by reference therein, since the end of the Company’s most recent audited fiscal year, there has been (i) no material weakness in the Company’s internal control over financial reporting (whether or not remediated) and (ii) no change in the Company’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting.

     (gg) No Unlawful Contributions or Other Payments. Neither the Company nor any of its Subsidiaries nor, to the best of the Company’s knowledge, any employee or agent of the Company or any Subsidiary, has made any contribution or other payment to any official of, or candidate for, any federal, state or foreign office in violation of any applicable law or of the character necessary to be disclosed in the Preliminary Prospectus or the Prospectus in order to make the statements therein not misleading.

     (hh) No Conflict with Money Laundering Laws. The operations of the Company and its Subsidiaries are and have been conducted at all times in compliance with applicable financial recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the money laundering statutes of all applicable jurisdictions, the rules and regulations thereunder and any related or similar rules, regulations or guidelines issued, administered or enforced by any governmental agency (collectively, the “Money Laundering Laws”) and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its Subsidiaries with respect to the Money Laundering Laws is pending or, to the Company’s knowledge, threatened.

     (ii) No Conflict with OFAC Laws. Neither the Company nor any of its Subsidiaries nor, to the Company’s knowledge, any director, officer, agent, employee or affiliate of the Company or any of its Subsidiaries is currently subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department (“OFAC”); and the Company will not directly or indirectly use the proceeds of the offering, or lend, contribute or otherwise make available such proceeds, to any Subsidiary, joint venture partner or other person or entity, for the purpose of financing the activities of any person currently subject to any U.S. sanctions administered by OFAC.

     (jj) Compliance with Environmental Laws. Except as would not, individually or in the aggregate, result in a Material Adverse Change: (i) neither the Company nor any of its Subsidiaries is in violation of any federal, state, local or foreign law or regulation relating to pollution or protection of human health or the environment (including, without limitation, ambient air, surface water, groundwater, land surface or subsurface strata) or wildlife, including without limitation, laws and regulations relating to emissions, discharges, releases or threatened releases of chemicals, pollutants, contaminants, wastes, toxic substances, hazardous substances, petroleum and petroleum products (collectively, “Materials of Environmental Concern”), or otherwise relating to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Materials of Environmental Concern (collectively, “Environmental

Laws”), which violation includes, but is not limited to, noncompliance with any permits or other governmental authorizations required for the operation of the business of the Company or its Subsidiaries under applicable Environmental Laws, or noncompliance with the terms and conditions thereof, nor has the Company or any of its Subsidiaries received any written communication, whether from a governmental authority, citizens group, employee or otherwise, that alleges that the Company or any of its Subsidiaries is in violation of any Environmental Law; (ii) there is no claim, action or cause of action filed with a court or governmental authority, no investigation with respect to which the Company has received written notice, and no written notice by any person or entity alleging potential liability for investigatory costs, cleanup costs, governmental responses costs, natural resources damages, property damages, personal injuries, attorneys’ fees or penalties arising out of, based on or resulting from the presence, or release into the environment, of any Material of Environmental Concern at any location owned, leased or operated by the Company or any of its Subsidiaries, now or in the past (collectively, “Environmental Claims”), pending or, to the best of the Company’s knowledge, threatened against the Company or any of its Subsidiaries or any person or entity whose liability for any Environmental Claim the Company or any of its Subsidiaries has retained or assumed either contractually or by operation of law; and (iii) to the best of the Company’s knowledge, there are no past or present actions, activities, circumstances, conditions, events or incidents, including, without limitation, the release, emission, discharge, presence or disposal of any Material of Environmental Concern, that reasonably could result in a violation of any Environmental Law or form the basis of a potential Environmental Claim against the Company or any of its Subsidiaries or against any person or entity whose liability for any Environmental Claim the Company or any of its Subsidiaries has retained or assumed either contractually or by operation of law.

     (kk) ERISA Compliance. The Company and its Subsidiaries and any “employee benefit plan” (as defined under the Employee Retirement Income Security Act of 1974, as amended, and the regulations and published interpretations thereunder (collectively, “ERISA”)) established or maintained by the Company, its Subsidiaries or their “ERISA Affiliates” (as defined below) are in compliance with ERISA, except for any such noncompliance as would not, individually or in the aggregate, reasonably be expected to result in a Material Adverse Change. “ERISA Affiliate” means, with respect to the Company or a Subsidiary, any member of any group of organizations described in Section 414(b), (c), (m) or (o) of the Internal Revenue Code of 1986, as amended, and the regulations and published interpretations thereunder (the “Code”), of which the Company or such Subsidiary is a member. No “reportable event” (as defined under ERISA) has occurred or is reasonably expected to occur with respect to any “employee benefit plan” established or maintained by the Company, its Subsidiaries or any of their ERISA Affiliates. No “employee benefit plan” (as defined in Section 3(3) of ERISA) established or maintained by the Company, its Subsidiaries or any of their ERISA Affiliates, if such “employee benefit plan” were terminated, would have any “amount of unfunded benefit liabilities” (as defined under ERISA) that could reasonably be expected to result in a Material Adverse Change. Neither the Company, its Subsidiaries nor any of their ERISA Affiliates has incurred or reasonably expects to incur any liability under (i) Title IV of ERISA with respect to termination of, or withdrawal from, any “employee benefit plan” or (ii) Section 412, 4971, 4975 or 4980B of the Code that could reasonably be expected to result in a Material Adverse Change. Each “employee benefit plan” established or maintained by the Company, its Subsidiaries or any of their ERISA Affiliates that is intended to be qualified under Section 401(a) of the Code is so qualified and nothing has occurred, including by action or failure to act, which would cause the

loss of such qualification, that has given or would give rise to any tax, penalty or other liability that could reasonably be expected to result in a Material Adverse Change.

     (ll) Brokers. Other than the Underwriters, there is no broker, finder or other party that is entitled to receive from the Company any brokerage or finder’s fee or other fee or commission as a result of any transactions contemplated by this Agreement.

     (mm) No Outstanding Loans or Other Indebtedness. There are no outstanding loans, advances (except normal advances for business expenses in the ordinary course of business) or guarantees or indebtedness by the Company to or for the benefit of any of the officers or directors of the Company or any of the members of any of them, except as disclosed in the Disclosure Package and the Prospectus.

     (nn) Sarbanes-Oxley Compliance. The Company is in compliance in all material respects with applicable provisions of the Sarbanes-Oxley Act of 2002 and the rules and regulations promulgated in connection therewith (the “Sarbanes-Oxley Act”) that are effective as of the date of this Agreement.

     (oo) Subsidiaries. The Subsidiaries listed on Annex A attached hereto are the only significant subsidiaries of the Company as defined by Rule 1-02 of Regulation S-X.

     (pp) Lending Relationship. Except as disclosed in the Disclosure Package and the Prospectus, the Company (i) does not have any material lending or other relationship with any bank or lending affiliate of any Underwriter and (ii) does not intend to use any of the proceeds from the sale of the Common Shares hereunder to repay any outstanding debt owed to any affiliate of any Underwriter.

     (qq) Forward-Looking Statements. No forward-looking statement (within the meaning of Section 27A of the Act and Section 21E of the Exchange Act) or presentation of market-related or statistical data contained in the Preliminary Prospectus and the Prospectus has been made or reaffirmed without a reasonable basis or has been disclosed in other than good faith.

     (rr) Other Agreements. Each of (i) the Investors Rights Agreement, dated August 14, 2006, by and among the Company, Bridas International Holdings, Ltd., Bridas Central Company, Ltd. and Associated Petroleum Investors Limited (including but not limited to Section 3 of such agreement) and (ii) the Asset Purchase Agreement, dated October 25, 2006, by and between the Company and Oil & Gas Rental (including but not limited to Section 9.10 of such agreement), are legal, valid and binding obligations of each party thereto, enforceable against each of the parties thereto.

     Any certificate signed by an officer of the Company and delivered to the Representative or to counsel for the Underwriters shall be deemed to be a representation and warranty by the Company to each Underwriter as to the matters set forth therein.

     Section 2. Purchase, Sale and Delivery of the Shares.

     (a) The Firm Shares. The Company agrees to issue and sell to the several Underwriters the Firm Shares upon the terms herein set forth. On the basis of the

representations, warranties and agreements herein contained, and upon the terms but subject to the conditions herein set forth, the Underwriters agree, severally and not jointly, to purchase from the Company the respective number of Firm Shares set forth opposite their names on Schedule A. The purchase price per Firm Common Share to be paid by the several Underwriters to the Company shall be $16.7675 per share.

     (b) The Closing Date. Delivery of certificates for the Firm Shares to be purchased by the Underwriters and payment therefor shall be made at the offices of Shearman & Sterling LLP, 599 Lexington Avenue, New York, New York 10022 (or such other place as may be agreed to by the Company and the Representative) at 9:00 a.m. New York time, on January 29, 2007, or such other time and date as the Representative shall designate by notice to the Company (the time and date of such closing are called the “Closing Date”).

     (c) The Optional Shares; the Subsequent Closing Date. In addition, on the basis of the representations, warranties and agreements herein contained, and upon the terms but subject to the conditions herein set forth, the Company hereby grants an option to the several Underwriters to purchase, severally and not jointly, up to an aggregate of 900,000 Optional Shares from the Company at the purchase price per share to be paid by the Underwriters for the Firm Shares. The option granted hereunder may be exercised at any time and from time to time upon notice by the Representative to the Company, which notice may be given at any time within 30 days from the date of this Agreement. Such notice shall set forth (i) the aggregate number of Optional Shares as to which the Underwriters are exercising the option, (ii) the names and denominations in which the certificates for the Optional Shares are to be registered and (iii) the time, date and place at which such certificates will be delivered (which time and date may be simultaneous with, but not earlier than, the Closing Date; and in such case the term “Closing Date” shall refer to the time and date of delivery of certificates for the Firm Shares and the Optional Shares). Each time and date of delivery, if subsequent to the Closing Date, is called a “Subsequent Closing Date” and shall be determined by the Representative and shall not be earlier than three nor later than five full business days after delivery of such notice of exercise. If any Optional Shares are to be purchased, the Company agrees to sell each Underwriter the number of Optional Shares (subject to such adjustments to eliminate fractional shares as the Representative may determine) that bears the same proportion to the total number of Optional Shares to be purchased as the number set forth on Schedule A opposite the name of each Underwriter bears to 900,000 and each Underwriter agrees, severally and not jointly, to purchase the number of Optional Shares (subject to such adjustments to eliminate fractional shares as the Representative may determine) that bears the same proportion to the total number of Optional Shares to be purchased as the number of Firm Shares set forth on Schedule A opposite the name of such Underwriter bears to the total number of Firm Shares.

     (d) Public Offering of the Shares. The Representative hereby advises the Company that the Underwriters intend to offer for sale to the public, as described in the Prospectus, their respective portions of the Shares as soon after this Agreement has been executed and the Registration Statement has been declared effective as the Representative, in its sole judgment, has determined is advisable and practicable.

     (e) Payment for the Shares. Payment for the Shares shall be made at the Closing Date (and, if applicable, at any Subsequent Closing Date) by wire transfer of immediately available funds to the order of the Company.

     It is understood that the Representative has been authorized, for its own account and the accounts of the several Underwriters, to accept delivery of and receipt for, and make payment of the purchase price for, the Firm Shares and any Optional Shares the Underwriters have agreed to purchase. RBC Capital Markets Corporation, individually and not as the Representative of the Underwriters, may (but shall not be obligated to) make payments for any Shares to be purchased by any Underwriter whose funds shall not have been received by RBC Capital Markets Corporation by the Closing Date or any Subsequent Closing Date, as the case may be, for the account of such Underwriter, but any such payment shall not relieve such Underwriter from any of its obligations under this Agreement.

     (f) Delivery of the Shares. Delivery of the Firm Shares and the Optional Shares shall be made through the facilities of The Depository Trust Company unless the Representative shall otherwise instruct. Time shall be of the essence, and delivery at the time and place specified in this Agreement is a further condition to the obligations of the Underwriters.

     (g) Delivery of Prospectus to the Underwriters. Not later than 10:00 a.m. on the second business day following the date the Shares are first released by the Underwriters for sale to the public, the Company shall deliver or cause to be delivered, copies of the Prospectus in such quantities and at such places as the Representative shall request.

     (h) Selling Restrictions. Each of the Underwriters represents and agrees that:

     (i) European Economic Area. In relation to each Member State of the European Economic Area which has implemented the Prospectus Directive (each, a “Relevant Member State”) it has not made and will not make an offer of the shares of Common Stock to the public in that Relevant Member State except that it may, with effect from and including the Relevant Implementation Date, make an offer of shares of Common Stock to the public in that Relevant Member State:

     (A) in (or in Germany, where the offer starts within) the period beginning on the date of publication of a prospectus in relation to those             shares of Common Stock which have been approved by the competent authority in that Relevant Member State or, where appropriate, approved in another Relevant Member State and notified to the competent authority in that Relevant Member State, all in accordance with the Prospectus Directive and ending on the date which is 12 months after the date of such publication;

     (B) at any time to legal entities which are authorized or regulated to operate in the financial markets or, if not so authorized or regulated, whose corporate purpose is solely to invest in securities;

     (C) at any time to any legal entity which has two or more of (1) an average of at least 250 employees during the last financial year; (2) a

total balance sheet of more than €43,000,000 and (3) an annual net turnover of more than €50,000,000 as shown in its last annual or consolidated accounts; or

     (D) at any time in any other circumstances which do not require the publication by the issuer of a prospectus pursuant to Article 3 of the Prospectus Directive.

     For the purposes of this provision, the expression an “offer of shares Common Stock to the public” in relation to any shares of Common Stock in any Relevant Member State means to communication in any form and by any means of sufficient information on the terms of the offer and the shares of Common Stock to be offered so as to enable an investor to decide to purchase or subscribe for the shares, as the same may be varied in that Member State by any measure implementing the Prospectus Directive in that Member State and the expression “Prospectus Directive” means Directive 2003/71/EC and includes any relevant implementing measure in each Relevant Member State.

     (ii) United Kingdom. (A) No deposit taking: (1) is a person whose ordinary activities involve it in acquiring, holding, managing or disposing of investments (as principal or agent) for the purposes of its business; and (2) it has not offered or sold and will not offer or sell any shares of Common Stock other than to persons whose ordinary activities involve them in acquiring, holding, managing or disposing of investments (as principal or agent) for the purposes of their businesses or who it is reasonable to expect will acquire, hold, manage or dispose of investments (as principal or agent) for the purposes of their businesses where the issue of the shares of Common Stock would otherwise constitute a contravention of Section 19 of the Financial Services and Markets Act of 2000, or the FSMA, by the Company.

     (B) Financial promotion: it has only communicated or caused to be communicated and will only communicate or cause to be communicated an invitation or inducement to engage in investment activity (within the meaning of Section 21 of the FSMA) received by it in connection with the issue or sale of any shares of Common Stock in circumstances in which Section 21(1) of the FSMA does not, or in the case of the Company, would not, if it was not an authorized institution, apply to the Company; and

     (C) General compliance: it has complied and will comply with all applicable provisions of the FSMA with respect to anything done by it in relation to any shares of Common Stock in, from or otherwise involving the United Kingdom.

     (iii) Switzerland. The shares of Common Stock may not and will not be publicly offered, distributed or redistributed on a professional basis in or from

Switzerland and neither the Prospectus nor any other solicitation for investments in the shares of Common Stock may be communicated or distributed in Switzerland in any way that could constitute a public offering within the meaning of Articles 1156 or 652a of the Swiss Code of Obligations or of Article 2 of the Federal Act on Investment Funds of March 18, 1994. The Prospectus is not a prospectus within the meaning of Articles 1156 and 652a of the Swiss Code of Obligations or a listing prospectus according to article 32 of the Listing Rules of the Swiss exchange and may not comply with the information standards required thereunder.

     Section 3. Covenants of the Company. The Company covenants and agrees with each Underwriter as follows:

     (a) Representative’s Review of Proposed Amendments and Supplements. During the period beginning on the Applicable Time and ending on the later of the Closing Date or such date, as in the opinion of counsel for the Underwriters, the Prospectus is no longer required by law to be delivered in connection with sales by an Underwriter or dealer, including in circumstances where such requirement may be satisfied pursuant to Rule 172 (the “Prospectus Delivery Period”), prior to amending or supplementing the Registration Statement, the Disclosure Package or the Prospectus, subject to Section 3(e), the Company shall furnish to the Representative for review a copy of each such proposed amendment or supplement, and the Company shall not file or use any such proposed amendment or supplement to which the Representative reasonably objects.

     (b) Securities Act Compliance. After the date of this Agreement, the Company shall promptly advise the Representative in writing (i) when the Registration Statement, if not effective at the Execution Time, shall have become effective, (ii) of the receipt of any comments of, or requests for additional or supplemental information from, the Commission, (iii) of the time and date of any filing of any post-effective amendment to the Registration Statement or any amendment or supplement to any preliminary prospectus or the Prospectus, (iv) of the time and date that any post-effective amendment to the Registration Statement becomes effective and (v) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or of any order or notice preventing or suspending the use of the Registration Statement, any preliminary prospectus or the Prospectus, or of any proceedings to remove, suspend or terminate from listing or quotation the Common Stock from any securities exchange upon which it is listed for trading or included or designated for quotation, or of the threatening or initiation of any proceedings for any of such purposes. The Company shall use its best efforts to prevent the issuance of any such stop order or notice of prevention or suspension of such use. If the Commission shall enter any such stop order or issue any such notice at any time, the Company will use its best efforts to obtain the lifting or reversal of such order or notice at the earliest possible moment, or, subject to Section 3(a), will file an amendment to the Registration Statement or will file a new registration statement and use its best efforts to have such amendment or new registration statement declared effective as soon as practicable. Additionally, the Company agrees that it shall comply with the provisions of Rules 424(b) and 430A, as applicable, under the Securities Act, including with respect to the timely filing of documents thereunder, and will use its reasonable efforts to confirm that any filings made by the Company under such Rule 424(b) were received in a timely manner by the Commission.

     (c) Exchange Act Compliance. During the Prospectus Delivery Period, the Company will file all documents required to be filed with the Commission pursuant to Section 13, 14 or 15 of the Exchange Act in the manner and within the time periods required by the Exchange Act.

     (d) Amendments and Supplements to the Registration Statement, Disclosure Package and Prospectus and Other Securities Act Matters. If, during the Prospectus Delivery Period, any event or development shall occur or condition exist as a result of which the Disclosure Package or the Prospectus as then amended or supplemented would include any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein in the light of the circumstances under which they were made or then prevailing, as the case may be, not misleading, or if it shall be necessary to amend or supplement the Disclosure Package or the Prospectus, or to file under the Exchange Act any document incorporated by reference in the Disclosure Package or the Prospectus, in order to make the statements therein, in the light of the circumstances under which they were made or then prevailing, as the case may be, not misleading, or if in the opinion of the Representative it is otherwise necessary or advisable to amend or supplement the Registration Statement, the Disclosure Package or the Prospectus, or to file under the Exchange Act any document incorporated by reference in the Disclosure Package or the Prospectus, or to file a new registration statement containing the Prospectus, in order to comply with law, including in connection with the delivery of the Prospectus, the Company agrees to (i) notify the Representative of any such event or condition and (ii) promptly prepare (subject to Sections 3(a) and 3(e) hereof), file with the Commission (and use its best efforts to have any amendment to the Registration Statement or any new registration statement to be declared effective) and furnish at its own expense to the Underwriters and to dealers, amendments or supplements to the Registration Statement, the Disclosure Package or the Prospectus, or any new registration statement, necessary in order to make the statements in the Disclosure Package or the Prospectus as so amended or supplemented, in the light of the circumstances under which they were made or then prevailing, as the case may be, not misleading or so that the Registration Statement, the Disclosure Package or the Prospectus, as amended or supplemented, will comply with applicable law.

     (e) Permitted Free Writing Prospectuses. The Company represents that it has not made, and agrees that, unless it obtains the prior written consent of the Representative, it will not make, any offer relating to the Shares that constitutes or would constitute an Issuer Free Writing Prospectus or that otherwise constitutes or would constitute a “free writing prospectus” (as defined in Rule 405 of the Securities Act) or a portion thereof required to be filed by the Company with the Commission or retained by the Company under Rule 433 of the Securities Act; provided that the prior written consent of the Representative hereto shall be deemed to have been given in respect of the Free Writing Prospectus included in Schedule B hereto. Any such free writing prospectus consented to by the Representative is hereinafter referred to as a “Permitted Free Writing Prospectus”. The Company agrees that (i) it has treated and will treat, as the case may be, each Permitted Free Writing Prospectus as an Issuer Free Writing Prospectus, and (ii) has complied and will comply, as the case may be, with the requirements of Rules 164 and 433 of the Securities Act applicable to any Permitted Free Writing Prospectus, including in respect of timely filing with the Commission, legending and record keeping.

     (f) Copies of any Amendments and Supplements to the Prospectus. The Company agrees to furnish the Representative, without charge, during the Prospectus Delivery Period, as

many copies of the Prospectus and any amendments and supplements thereto (including any documents incorporated or deemed incorporated by reference therein) and the Disclosure Package as the Representative may reasonably request.

     (g) Copies of the Registration Statement and the Prospectus. The Company will furnish to the Representative and counsel for the Underwriters signed copies of the Registration Statement (including exhibits thereto) and, so long as delivery of a prospectus by an Underwriter or dealer may be required by the Act, as many copies of each preliminary prospectus, the Prospectus and any supplement thereto and the Disclosure Package as the Representative may reasonably request.

     (h) Blue Sky Compliance. The Company shall cooperate with the Representative and counsel for the Underwriters to qualify or register the Shares for sale under (or obtain exemptions from the application of) the state securities or blue sky laws or Canadian provincial Securities laws of those jurisdictions designated by the Representative, shall comply with such laws and shall continue such qualifications, registrations and exemptions in effect so long as required for the distribution of the Shares. The Company shall not be required to qualify as a foreign corporation or to take any action that would subject it to general service of process in any such jurisdiction where it is not presently qualified or where it would be subject to taxation as a foreign corporation, other than those arising out of the offering or sale of the Shares in any jurisdiction where it is not now so subject. The Company will advise the Representative promptly of the suspension of the qualification or registration of (or any such exemption relating to) the Shares for offering, sale or trading in any jurisdiction or any initiation or threat of any proceeding for any such purpose, and in the event of the issuance of any order suspending such qualification, registration or exemption, the Company shall use its commercially reasonable efforts to obtain the withdrawal thereof at the earliest possible moment.

     (i) Use of Proceeds. The Company shall apply the net proceeds from the sale of the Shares sold by it in the manner described under the caption “Use of Proceeds” in the Disclosure Package and the Prospectus.

     (j) Transfer Agent. The Company shall engage and maintain, at its expense, a registrar and transfer agent for the Common Stock.

     (k) Earnings Statement. As soon as practicable, the Company will make generally available to its security holders and to the Representative an earnings statement (which need not be audited) covering the twelve-month period beginning with the first fiscal quarter of the Company occurring after the date of this Agreement that satisfies the provisions of Section 11(a) of the Securities Act and Rule 158 under the Securities Act.

     (l) Periodic Reporting Obligations. During the Prospectus Delivery Period the Company shall file, on a timely basis, with the Commission and the American Stock Exchange all reports and documents required to be filed under the Exchange Act. Additionally, the Company shall report the use of proceeds from the issuance of the Shares as may be required under Rule 463 under the Securities Act.

     (m) Listing. The Company will use its best efforts to list, subject to notice of issuance, the Shares on the American Stock Exchange.

     (n) Agreement Not to Offer or Sell Additional Shares. During the period commencing on the date hereof and ending on the 90th day following the date of the Prospectus, the Company will not, without the prior written consent of the Representative (which consent may be withheld at the sole discretion of the Representative), directly or indirectly, sell, offer, contract or grant any option to sell, pledge, transfer or establish an open “put equivalent position” or liquidate or decrease a “call equivalent position” within the meaning of Rule 16a-1(h) under the Exchange Act, or otherwise dispose of or transfer (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition of), or announce the offering of, or file any registration statement under the Securities Act in respect of, any shares of Common Stock, options or warrants to acquire shares of the Common Stock or securities exchangeable or exercisable for or convertible into shares of Common Stock (other than as contemplated by this Agreement with respect to the Shares); provided, however, that the Company may (i) issue shares of its Common Stock or options to purchase its Common Stock, or Common Stock upon exercise of options, pursuant to any stock option, stock bonus or other stock plan or arrangement described in the Prospectus, but only if the holders of such shares, options, or shares issued upon exercise of such options, agree in writing not to sell, offer, dispose of or otherwise transfer any such shares or options during such 90-day period without the prior written consent of the Representative (which consent may be withheld at the sole discretion of the Representative) and (ii) file one or more selling stockholder registration statements registering the offering and sale of up to 500,000 shares of Common Stock. Notwithstanding the foregoing, if (x) during the last 17 days of the 90-day restricted period the Company issues an earnings release or material news or a material event relating to the Company occurs, or (y) prior to the expiration of the 90-day restricted period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the 90-day period, the restrictions imposed in this clause shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event; provided, however, that such restrictions shall not be so extended solely by virtue of the publishing or distribution by any Underwriter of any research regarding any earnings release, material news or a material event, if such research report complies with Rule 139 of the Securities Act and the Common Stock is “actively traded,” as defined in Rule 101(c)(1) of Regulation M under the Exchange Act. The Company will provide the Representative and any co-managers and each individual subject to the restricted period pursuant to the lock-up letters described in Section 5(h) with prior notice of any such announcement that gives rise to an extension of the restricted period.

     (o) Compliance with Sarbanes-Oxley Act. The Company will comply with all applicable securities and other laws, rules and regulations, including, without limitation, the Sarbanes-Oxley Act, and use its best efforts to cause the Company’s directors and officers, in their capacities as such, to comply with such laws, rules and regulations, including, without limitation, the provisions of the Sarbanes-Oxley Act.

     (p) Future Reports to Stockholders. To the extent not available via EDGAR, to furnish to its stockholders as soon as practicable after the end of each fiscal year an annual report (including a balance sheet and statements of income, stockholders’ equity and cash flows of the

Company and its consolidated subsidiaries certified by independent public accountants) and, as soon as practicable after the end of each of the first three quarters of each fiscal year (beginning with the fiscal quarter ending after the effective date of the Registration Statement), to make available to its stockholders consolidated summary financial information of the Company and its subsidiaries for such quarter in reasonable detail.

     (q) Future Reports to the Representative. During the period of five years hereafter the Company will furnish or make available via EDGAR to the Representative at One Liberty Plaza, New York, New York 10006, Attention: Joe Morea, (i) as soon as practicable after the end of each fiscal year, copies of the Annual Report of the Company containing the balance sheet of the Company as of the close of such fiscal year and statements of income, stockholders’ equity and cash flows for the year then ended and the opinion thereon of the Company’s independent public or certified public accountants; (ii) as soon as practicable after the filing thereof, copies of each proxy statement, Annual Report on Form 10-K, Quarterly Report on Form 10-Q, Current Report on Form 8-K or other report filed by the Company with the Commission, the NASD or any securities exchange; and (iii) as soon as available, copies of any report or communication of the Company mailed generally to holders of its capital stock.

     (r) Investment Limitation. The Company shall not invest, or otherwise use the proceeds received by the Company from its sale of the Shares in such a manner as would require the Company or any of its Subsidiaries to register as an investment company under the Investment Company Act.

     (s) No Manipulation of Price. The Company will not take, directly or indirectly, any action designed to cause or result in, or that has constituted or might reasonably be expected to constitute, under the Exchange Act or otherwise, the stabilization or manipulation of the price of any securities of the Company to facilitate the sale or resale of the Shares.

     (t) Existing Lock-Up Agreement. The Company will enforce all existing agreements between the Company and any of its security holders that prohibit the sale, transfer, assignment, pledge or hypothecation of any of the Company’s securities in connection with the Company’s initial public offering. In addition, the Company will direct the transfer agent to place stop transfer restrictions upon any such securities of the Company that are bound by such existing “lock-up” agreements for the duration of the periods contemplated in such agreements.

     The Representative, on behalf of the several Underwriters, may, in its sole discretion, waive in writing the performance by the Company of any one or more of the foregoing covenants or extend the time for their performance. Notwithstanding the foregoing, the Representative, for the benefit of each of the other Underwriters, agrees not to consent to any action proposed to be taken by the Company or any other holder of the Company’s securities that would otherwise be prohibited by, or to waive compliance by the Company or any such other security holder with the provisions of, Section 3(n) above or any lock-up agreement delivered pursuant to Section 5(h) below without giving each of the other Underwriters at least 17 days’ prior notice (or such shorter notice as each of the other Underwriters may deem acceptable to permit compliance with applicable provisions of NASD Conduct Rule 2711(f) restricting publication and distribution of research and public appearances by research analysts before and after the expiration, waiver or termination of a lock-up agreement).

     Section 4. Payment of Expenses. The Company agrees to pay all costs, fees and expenses incurred in connection with the performance of its obligations hereunder and in connection with the transactions contemplated hereby, including without limitation (i) all expenses incident to the issuance and delivery of the Shares (including all printing and engraving costs), (ii) all fees and expenses of the registrar and transfer agent of the Common Stock, (iii) all necessary issue, transfer and other stamp taxes in connection with the issuance and sale of the Shares to the Underwriters, (iv) all fees and expenses of the Company’s counsel, independent public or certified public accountants and other advisors, (v) all costs and expenses incurred in connection with the preparation, printing, filing, shipping and distribution of the Registration Statement (including financial statements, exhibits, schedules, consents and certificates of experts), each Issuer Free Writing Prospectus, each preliminary prospectus and the Prospectus, and all amendments and supplements thereto, and this Agreement, (vi) all filing fees, attorneys’ fees and expenses incurred by the Company or the Underwriters in connection with qualifying or registering (or obtaining exemptions from the qualification or registration of) all or any part of the Shares for offer and sale under the state securities or blue sky laws or the provincial securities laws of Canada, and, if requested by the Representative, preparing and printing a “Blue Sky Survey” or memorandum, and any supplements thereto, advising the Underwriters of such qualifications, registrations and exemptions, (vii) the filing fees incident to, and the reasonable fees and expenses of counsel for the Underwriters in connection with, the NASD’s review and approval of the Underwriters’ participation in the offering and distribution of the Shares, (viii) the fees and expenses associated with listing of the Shares on the American Stock Exchange, (ix) all transportation and other expenses incurred in connection with presentations to prospective purchasers of the Shares, except that the Company and the Underwriters will each pay 50% of the cost of privately chartered airplanes used for such purposes and (x) all other fees, costs and expenses referred to in Item 13 of Part II of the Registration Statement. Except as provided in this Section 4, Section 6, Section 8 and Section 9 hereof, the Underwriters shall pay their own expenses, including the fees and disbursements of their counsel.

     Section 5. Conditions of the Obligations of the Underwriters. The obligations of the several Underwriters to purchase and pay for the Shares as provided herein on the Closing Date and, with respect to the Optional Shares, any Subsequent Closing Date, shall be subject to the accuracy in all material respects of the representations and warranties on the part of the Company set forth in Section 1 hereof that are not qualified by materiality as of the date hereof and as of the Closing Date as though then made and, with respect to the Optional Shares, as of any Subsequent Closing Date as though then made, to the accuracy of the representations and warranties on the part of the Company set forth in Section 1 hereof that are qualified by materiality as of the date hereof and as of the Closing Date as though then made and, with respect to the Optional Shares, as of any Subsequent Closing Date as though then made, to the accuracy of the statements of the Company made in any certificates pursuant to the provisions hereof, to the timely performance by the Company of its covenants and other obligations hereunder, and to each of the following additional conditions:

     (a) Accountants’ Comfort Letter. On the date hereof, the Representative shall have received from the accountants listed on Schedule E hereto, in respect of each entity set forth opposite such accountant’s name on Schedule E hereto, a letter from each such accountant dated the date hereof addressed to the Underwriters in form and substance satisfactory to the Underwriters, containing statements and information of the type ordinarily included in

accountants’ “comfort letters” to underwriters, delivered according to Statement of Auditing Standards No. 72 (or any successor bulletin), with respect to the audited and unaudited financial statements and certain financial information contained in the Registration Statement and the Prospectus, and the specified date referred to therein for the carrying out of procedures shall be no more than three days prior to the date hereof.

     (b) Compliance with Registration Requirements; No Stop Order; No Objection from NASD. For the period from and after effectiveness of this Agreement and prior to the Closing Date and, with respect to the Optional Shares, any Subsequent Closing Date:

     (i) the Company shall have filed the Prospectus with the Commission (including the information required by Rule 430A under the Securities Act) in the manner and within the time period required by Rule 424(b) under the Securities Act; or the Company shall have filed a post-effective amendment to the Registration Statement containing the information required by such Rule 430A, and such post-effective amendment shall have become effective;

     (ii) all material required to be filed by the Company pursuant to Rule 433(d) under the Securities Act shall have been filed with the Commission within the applicable time periods prescribed for such filings under such Rule 433;

     (iii) no stop order suspending the effectiveness of the Registration Statement, or any post-effective amendment to the Registration Statement, shall be in effect and no proceedings for such purpose shall have been instituted or threatened by the Commission; and

     (iv) the NASD shall have raised no objection to the fairness and reasonableness of the underwriting terms and arrangements.

     (c) No Material Adverse Change or Ratings Agency Change. For the period from and after the date of this Agreement and prior to the Closing Date and, with respect to the Optional Shares, any Subsequent Closing Date:

     (i) there shall not have occurred any Material Adverse Change; and

     (ii) there shall not have occurred any downgrading, nor shall any notice have been given of any intended or potential downgrading or of any review for a possible change that does not indicate the direction of the possible change, in the rating accorded any securities of the Company or any of its subsidiaries by any “nationally recognized statistical rating organization” as such term is defined for purposes of Rule 436(g)(2) under the Securities Act.

     (d) Opinion of Counsel for the Company. On the Closing Date and any Subsequent Closing Date, the Representative shall have received the favorable opinion of Andrews Kurth LLP, counsel for the Company, dated as of such Closing Date, the form of which is attached as Exhibit A.

     (e) Opinion of Counsel for the Underwriters. On the Closing Date and any Subsequent Closing Date, the Representative shall have received the favorable opinion of Shearman & Sterling LLP, counsel for the Underwriters, dated as of such Closing Date, in form and substance satisfactory to, and addressed to, the Underwriters, with respect to the issuance and sale of the Shares, the Registration Statement, the Prospectus (together with any supplement thereto), the Disclosure Package and other related matters as the Representative may reasonably require, and the Company shall have furnished to such counsel such documents as they request for the purpose of enabling them to pass upon such matters.

     (f) Officers’ Certificate of the Company. On the Closing Date and any Subsequent Closing Date, the Representative shall have received a written certificate executed by the Chairman of the Board, Chief Executive Officer or President and the Chief Financial Officer or Chief Accounting Officer of the Company, dated as of such Closing Date, to the effect that the signers of such certificate have carefully examined the Registration Statement, the Prospectus and any amendment or supplement thereto, any Issuer Free Writing Prospectus and any amendment or supplement thereto and this Agreement, to the effect set forth in subsections (b) and (c) of this Section 5, and further to the effect that:

     (i) for the period from and after the date of this Agreement and prior to such Closing Date, there has not occurred any Material Adverse Change;

     (ii) the representations, warranties and covenants of the Company set forth in Section 1 of this Agreement not qualified by materiality are true and correct in all material respects and those representations, warranties and covenants of the Company set forth in Section 1 of this Agreement qualified by materiality are true and correct on and as of the Closing Date with the same force and effect as though expressly made on and as of such Closing Date; and

     (iii) the Company has complied with all the agreements hereunder and satisfied all the conditions on its part to be performed or satisfied hereunder at or prior to such Closing Date.

     (g) Bring-down Comfort Letter. On the Closing Date and any Subsequent Closing Date, the Representative shall have received from the accountants listed on Schedule E hereto, in respect of each entity set forth opposite such accountant’s name on Schedule E hereto, a letter dated such date, in form and substance satisfactory to the Representative, to the effect that they reaffirm the statements made in the letter furnished by them pursuant to subsection (a) of this Section 5, except that the specified date referred to therein for the carrying out of procedures shall be no more than three business days prior to the Closing Date or Subsequent Closing Date, as the case may be.

     (h) Lock-Up Agreement from Certain Securityholders of the Company. On or prior to the date hereof, the Company shall have furnished to the Representative an agreement in the form of Exhibit B hereto from each of the persons named on Schedule D hereto, and such agreement shall be in full force and effect on the Closing Date and any Subsequent Closing Date.

     (i) Additional Documents. On or before the Closing Date and any Subsequent Closing Date, the Representative and counsel for the Underwriters shall have received such information, documents and opinions as they may reasonably require for the purposes of enabling them to pass upon the issuance and sale of the Shares as contemplated herein, or in order to evidence the accuracy of any of the representations and warranties, or the satisfaction of any of the conditions or agreements, herein contained.

     If any condition specified in this Section 5 is not satisfied when and as required to be satisfied, this Agreement may be terminated by the Representative by notice to the Company at any time on or prior to the Closing Date and, with respect to the Optional Shares, at any time prior to the applicable Subsequent Closing Date, which termination shall be without liability on the part of any party to any other party, except that Section 4, Section 6, Section 8 and Section 9 shall at all times be effective and shall survive such termination.

     Section 6. Reimbursement of Underwriters’ Expenses. If this Agreement is terminated by the Representative pursuant to Section 5, Section 7, or Section 11, or if the sale to the Underwriters of the Shares on the Closing Date is not consummated because of any refusal, inability or failure on the part of the Company to perform any agreement herein or to comply with any provision hereof, the Company agrees to reimburse the Representative and the other Underwriters (or such Underwriters as have terminated this Agreement with respect to themselves), severally, upon demand for all out-of-pocket expenses that shall have been reasonably incurred by the Representative and the Underwriters in connection with the proposed purchase and the offering and sale of the Shares, including but not limited to fees and disbursements of counsel, printing expenses, travel expenses, postage, facsimile and telephone charges.

     Section 7. Effectiveness of this Agreement. This Agreement shall not become effective until the later of (i) the execution of this Agreement by the parties hereto and (ii) notification by the Commission to the Company and the Representative of the effectiveness of the Registration Statement under the Securities Act.

     Prior to such effectiveness, this Agreement may be terminated by any party by notice to each of the other parties hereto, and any such termination shall be without liability on the part of (a) the Company to any Underwriter, except that the Company shall be obligated to reimburse the expenses of the Representative and the Underwriters pursuant to Sections 4 and 6 hereof or (b) of any Underwriter to the Company.

     Section 8. Indemnification.

     (a) Indemnification of the Underwriters by the Company. The Company agrees to indemnify and hold harmless each Underwriter, its directors, officers, employees and agents and each person, if any, who controls any Underwriter within the meaning of the Securities Act and the Exchange Act against any loss, claim, damage, liability or expense, as incurred, to which such Underwriter or such officer, employee or controlling person may become subject, under the Securities Act, the Exchange Act or other federal or state statutory law or regulation, or at common law or otherwise (including in settlement of any litigation, if such settlement is effected with the written consent of the Company), insofar as such loss, claim, damage, liability or

expense (or actions in respect thereof as contemplated below) arises out of or is based (i) upon any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement, or any amendment thereto, or the omission or alleged omission therefrom of a material fact required to be stated therein or necessary to make the statements therein not misleading; or (ii) upon any untrue statement or alleged untrue statement of a material fact contained in any Issuer Free Writing Prospectus, any preliminary prospectus or the Prospectus (or any amendment or supplement thereto), or the omission or alleged omission therefrom of a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, and to reimburse each Underwriter, its officers, directors, employees, agents and each such controlling person for any and all expenses (including the fees and disbursements of counsel chosen by the Representative) as such expenses are reasonably incurred by such Underwriter or its officers, directors, employees, agents or such controlling person in connection with investigating, defending, settling, compromising or paying any such loss, claim, damage, liability, expense or action; provided, however, that the foregoing indemnity agreement shall not apply to any loss, claim, damage, liability or expense to the extent, but only to the extent, arising out of or based upon any untrue statement or alleged untrue statement or omission or alleged omission made in reliance upon and in conformity with written information furnished to the Company by the Representative expressly for use in the Registration Statement, any Issuer Free Writing Prospectus, any preliminary prospectus or the Prospectus (or any amendment or supplement thereto). The indemnity agreement set forth in this Section 8(a) shall be in addition to any liabilities that the Company may otherwise have.

     (b) Indemnification of the Company, its Directors and Officers. Each Underwriter agrees, severally and not jointly, to indemnify and hold harmless the Company, each of the Company’s directors, each of the Company’s officers and employees who signed the Registration Statement and each person, if any, who controls the Company within the meaning of the Securities Act or the Exchange Act, against any loss, claim, damage, liability or expense, as incurred, to which the Company, or any such director, officer, employee or controlling person may become subject, insofar as such loss, claim, damage, liability or expense (or actions in respect thereof as contemplated below) arises out of or is based upon any untrue or alleged untrue statement of a material fact contained in the Registration Statement, any Issuer Free Writing Prospectus, any preliminary prospectus or the Prospectus (or any amendment or supplement thereto), or arises out of or is based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, in each case to the extent, and only to the extent, that such untrue statement or alleged untrue statement or omission or alleged omission was made in the Registration Statement, any Issuer Free Writing Prospectus, any preliminary prospectus or the Prospectus (or any amendment or supplement thereto), in reliance upon and in conformity with written information furnished to the Company by the Representative expressly for use therein; and to reimburse the Company, or any such director, officer, employee or controlling person for any legal and other expenses reasonably incurred by the Company, or any such director, officer, employee or controlling person in connection with investigating, defending, settling, compromising or paying any such loss, claim, damage, liability, expense or action. The Company hereby acknowledges that the only information that the Underwriters have furnished to the Company expressly for use in the Registration Statement, any Issuer Free Writing Prospectus, any preliminary prospectus or the Prospectus (or any amendment or supplement thereto) are (i) the names of the Underwriters as set forth on the front and back covers of the

preliminary prospectus and the Prospectus and as further set forth in the table in the first paragraph under the caption “Underwriting” and (ii) the statements set forth in the table in the fourth paragraph, in the sixth paragraph and tenth, eleventh and twelfth paragraphs under the caption “Underwriting” in the preliminary prospectus and the Prospectus; and the Underwriters confirm that such statements are correct. The indemnity agreement set forth in this Section 8(b) shall be in addition to any liabilities that each Underwriter may otherwise have.

     (c) Notifications and Other Indemnification Procedures. Promptly after receipt by an indemnified party under this Section 8 of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against an indemnifying party under this Section 8, notify the indemnifying party in writing of the commencement thereof, but the failure to so notify the indemnifying party (i) will not relieve it from liability under paragraph (a) or (b) above unless and to the extent it did not otherwise learn of such action and such failure results in the forfeiture by the indemnifying party of substantial rights and defenses and (ii) will not, in any event, relieve the indemnifying party from any obligations to any indemnified party other than the indemnification obligation provided in paragraph (a) or (b) above. In case any such action is brought against any indemnified party and such indemnified party seeks or intends to seek indemnity from an indemnifying party, the indemnifying party will be entitled to participate in, and, to the extent that it shall elect, jointly with all other indemnifying parties similarly notified, by written notice delivered to the indemnified party promptly after receiving the aforesaid notice from such indemnified party, to assume the defense thereof with counsel reasonably satisfactory to such indemnified party; provided, however, if the defendants in any such action include both the indemnified party and the indemnifying party and the indemnified party shall have reasonably concluded that a conflict may arise between the positions of the indemnifying party and the indemnified party in conducting the defense of any such action or that there may be legal defenses available to it and/or other indemnified parties that are different from or additional to those available to the indemnifying party, the indemnified party or parties shall have the right to select separate counsel to assume such legal defenses and to otherwise participate in the defense of such action on behalf of such indemnified party or parties. Upon receipt of notice from the indemnifying party to such indemnified party of such indemnifying party’s election so to assume the defense of such action and approval by the indemnified party of counsel, which such approval shall not be unreasonably withheld, the indemnifying party will not be liable to such indemnified party under this Section 8 for any legal or other expenses subsequently incurred by such indemnified party in connection with the defense thereof unless (i) the indemnified party shall have employed separate counsel in accordance with the proviso to the preceding sentence (it being understood, however, that the indemnifying party shall not be liable for the expenses of more than one separate counsel (other than local counsel), reasonably approved by the indemnifying party (or by the Representative in the case of Section 8(b)), representing the indemnified parties who are parties to such action) or (ii) the indemnifying party shall not have employed counsel satisfactory to the indemnified party to represent the indemnified party within a reasonable time after notice of commencement of the action, in each of which cases the fees and expenses of counsel shall be at the expense of the indemnifying party.

     (d) Settlements. The indemnifying party under this Section 8 shall not be liable for any settlement of any proceeding effected without its written consent, which shall not be withheld unreasonably, but if settled with such consent or if there is a final judgment for the

plaintiff, the indemnifying party agrees to indemnify the indemnified party against any loss, claim, damage, liability or expense by reason of such settlement or judgment. Notwithstanding the foregoing sentence, if at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party for fees and expenses of counsel as contemplated by Section 8(c) hereof, the indemnifying party agrees that it shall be liable for any settlement of any proceeding effected without its written consent if (i) such settlement is entered into more than 30 days after receipt by such indemnifying party of the aforesaid request and (ii) such indemnifying party shall not have reimbursed the indemnified party in accordance with such request prior to the date of such settlement. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement, compromise or consent to the entry of judgment in any pending or threatened action, suit or proceeding in respect of which any indemnified party is or could have been a party and indemnity was or could have been sought hereunder by such indemnified party, unless such settlement, compromise or consent (x) includes an unconditional release of such indemnified party from all liability on claims that are the subject matter of such action, suit or proceeding and (y) does not include a statement as to or an admission of fault, culpability or a failure to act, by or on behalf of any indemnified party.

     Section 9. Contribution. If the indemnification provided for in Section 8 is for any reason unavailable to or otherwise insufficient to hold harmless an indemnified party in respect of any losses, claims, damages, liabilities or expenses referred to therein, then each indemnifying party shall contribute to the aggregate amount paid or payable by such indemnified party, as incurred, as a result of any losses, claims, damages, liabilities or expenses referred to therein (i) in such proportion as is appropriate to reflect the relative benefits received by the Company, on the one hand, and the Underwriters, on the other hand, from the offering of the Shares pursuant to this Agreement or (ii) if the allocation provided by clause (i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the Company, on the one hand, and the Underwriters, on the other hand, in connection with the statements or omissions or inaccuracies in the representations and warranties herein which resulted in such losses, claims, damages, liabilities or expenses, as well as any other relevant equitable considerations. The relative benefits received by the Company, on the one hand, and the Underwriters, on the other hand, in connection with the offering of the Shares pursuant to this Agreement shall be deemed to be in the same respective proportions as the total net proceeds from the offering of the Shares pursuant to this Agreement (before deducting expenses) received by the Company, and the total underwriting discount received by the Underwriters, in each case as set forth on the front cover page of the Prospectus bear to the aggregate initial public offering price of the Shares as set forth on such cover. The relative fault of the Company, on the one hand, and the Underwriters, on the other hand, shall be determined by reference to, among other things, whether any such untrue or alleged untrue statement of a material fact or omission or alleged omission to state a material fact or any such inaccurate or alleged inaccurate representation or warranty relates to information supplied by the Company, on the one hand, or the Underwriters, on the other hand, and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission.

     The amount paid or payable by a party as a result of the losses, claims, damages, liabilities and expenses referred to above shall be deemed to include, subject to the limitations set

forth in Section 8(c), any legal or other fees or expenses reasonably incurred by such party in connection with investigating or defending any action or claim.

     The Company and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 9 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation that does not take account of the equitable considerations referred to in this Section 9.

     Notwithstanding the provisions of this Section 9, no Underwriter shall be required to contribute any amount in excess of the underwriting commissions received by such Underwriter in connection with the Shares underwritten by it and distributed to the public. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Underwriters’ obligations to contribute pursuant to this Section 9 are several, and not joint, in proportion to their respective underwriting commitments as set forth opposite their names in Schedule A. For purposes of this Section 9, each director, officer, employee and agent of an Underwriter and each person, if any, who controls an Underwriter within the meaning of the Securities Act and the Exchange Act shall have the same rights to contribution as such Underwriter, and each director of the Company, each officer of the Company who signed the Registration Statement and each person, if any, who controls the Company within the meaning of the Securities Act and the Exchange Act shall have the same rights to contribution as the Company.

     Section 10. Default of One or More of the Several Underwriters. If, on the Closing Date or a Subsequent Closing Date, as the case may be, any one or more of the several Underwriters shall fail or refuse to purchase Shares that it or they have agreed to purchase hereunder on such date, and the aggregate number of Shares which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase does not exceed 10% of the aggregate number of the Shares to be purchased on such date, the other Underwriters shall be obligated, severally, in the proportions that the number of Firm Shares set forth opposite their respective names on Schedule A bears to the aggregate number of Firm Shares set forth opposite the names of all such non-defaulting Underwriters, or in such other proportions as may be specified by the Representative with the consent of the non-defaulting Underwriters, to purchase the Shares which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase on such date. If, on the Closing Date or a Subsequent Closing Date, as the case may be, any one or more of the Underwriters shall fail or refuse to purchase Shares and the aggregate number of Shares with respect to which such default occurs exceeds 10% of the aggregate number of Shares to be purchased on such date, and arrangements satisfactory to the Representative and the Company for the purchase of such Shares are not made within 48 hours after such default, this Agreement shall terminate without liability of any party to any other party, except that the provisions of Section 4, Section 6, Section 8 and Section 9 shall at all times be effective and shall survive such termination. In any such case either the Representative or the Company shall have the right to postpone the Closing Date or a Subsequent Closing Date, as the case may be, but in no event for longer than seven days in order that the required changes, if any, to the Registration Statement and the Prospectus or any other documents or arrangements may be effected.

     As used in this Agreement, the term “Underwriter” shall be deemed to include any person substituted for a defaulting Underwriter under this Section 10. Any action taken under this Section 10 shall not relieve any defaulting Underwriter from liability in respect of any default of such Underwriter under this Agreement.

     Section 11. Termination of this Agreement. Prior to the Closing Date, this Agreement may be terminated by the Representative by notice given to the Company if at any time: (i) trading or quotation in any of the Company’s securities shall have been suspended or limited by the Commission or by the American Stock Exchange, or trading in securities generally on the American Stock Exchange, the Nasdaq Stock Market or the New York Stock Exchange shall have been suspended or limited, or minimum or maximum prices shall have been generally established on any of such stock exchanges by the Commission or the NASD; (ii) a general banking moratorium shall have been declared by any of federal or New York authorities; (iii) there has been a material disruption in commercial banking or securities settlement, payment or clearance services in the United States; (iv) there shall have occurred any outbreak or escalation of national or international hostilities or any crisis or calamity, or any change in the United States or international financial markets, or any substantial change or development involving a prospective substantial change in United States’ or international political, financial or economic conditions, as in the judgment of the Representative is material and adverse and makes it impracticable to market the Shares in the manner and on the terms described in the Prospectus or to enforce contracts for the sale of securities; (v) in the reasonable judgment of the Representative there shall have occurred any Material Adverse Change; or (vi) the Company shall have sustained a loss by strike, fire, flood, earthquake, accident or other calamity of such character as in the judgment of the Representative would reasonably be expected to result in a Material Adverse Change. Any termination pursuant to this Section 11 shall be without liability on the part of (i) the Company to any Underwriter, except that the Company shall be obligated to reimburse the expenses of the Representative and the Underwriters pursuant to Sections 4 and 6 hereof, (ii) any Underwriter to the Company or (iii) any party hereto to any other party except that the provisions of Section 8 and Section 9 shall at all times be effective and shall survive such termination.

     Section 12. No Advisory or Fiduciary Responsibility. The Company acknowledges and agrees that: (i) the purchase and sale of the Shares pursuant to this Agreement, including the determination of the public offering price of the Shares and any related discounts and commissions, is an arm’s-length commercial transaction between the Company, on the one hand, and the several Underwriters, on the other hand, and the Company is capable of evaluating and understanding and understands and accepts the terms, risks and conditions of the transactions contemplated by this Agreement; (ii) in connection with each transaction contemplated hereby and the process leading to such transaction each Underwriter is and has been acting solely as a principal and is not the financial advisor, agent or fiduciary of the Company or its affiliates, stockholders, creditors or employees or any other party; (iii) no Underwriter has assumed or will assume an advisory, agency or fiduciary responsibility in favor of the Company with respect to any of the transactions contemplated hereby or the process leading thereto (irrespective of whether such Underwriter has advised or is currently advising the Company on other matters) and no Underwriter has any obligation to the Company with respect to the offering contemplated hereby except the obligations expressly set forth in this Agreement; (iv) the several Underwriters and their respective affiliates may be engaged in a broad range of transactions that involve

interests that differ from those of the Company and that the several Underwriters have no obligation to disclose any of such interests by virtue of any advisory, agency or fiduciary relationship; and (v) the Underwriters have not provided any legal, accounting, regulatory or tax advice with respect to the offering contemplated hereby and the Company has consulted its own legal, accounting, regulatory and tax advisors to the extent it deemed appropriate.

     This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Company and the several Underwriters, or any of them, with respect to the subject matter hereof. The Company hereby waives and releases, to the fullest extent permitted by law, any claims that the Company may have against the several Underwriters with respect to any breach or alleged breach of agency or fiduciary duty.

     Section 13. Representations and Indemnities to Survive Delivery. The respective indemnities, agreements, representations, warranties and other statements of the Company, of its officers and of the several Underwriters set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any (i) investigation made by or on behalf of any Underwriter, the officers or employees of any Underwriter, or any person controlling the Underwriter, the Company, the officers or employees of the Company, or any person controlling the Company, as the case may be, or (ii) acceptance of the Shares and payment for them hereunder, and will survive delivery of and payment for the Shares sold hereunder and any termination of this Agreement.

     Section 14. Notices. All communications hereunder shall be in writing and shall be mailed, hand delivered or telecopied and confirmed to the parties hereto as follows:

     If to the Representative:

RBC Capital Markets Corporation
One Liberty Plaza
New York, New York 10006
Facsimile: (212)  ###-###-####
Attention: Joe Morea

     If to the Company:

Allis-Chalmers Energy Inc.
5075 Westheimer, Suite 890
Houston, Texas 77056
Facsimile: (713)  ###-###-####
Attention: Theodore F. Pound III, Esq.

     with a copy (which shall not constitute notice) to:

Andrews Kurth LLP
600 Travis, Suite 400
Houston, Texas 77002
Facsimile: (713)  ###-###-####
Attention: Robert V. Jewell

     Any party hereto may change the address for receipt of communications by giving written notice to the others in accordance with this Section 14.

     Section 15. Successors and Assigns. This Agreement will inure to the benefit of and be binding upon the parties hereto, including any substitute Underwriters pursuant to Section 10 hereof, and to the benefit of (i) the Company, its directors, any person who controls the Company within the meaning of the Securities Act and the Exchange Act and any officer of the Company who signs the Registration Statement, (ii) the Underwriters, the officers, directors, employees and agents of the Underwriters, and each person, if any, who controls any Underwriter within the meaning of the Securities Act and the Exchange Act, and (iii) the respective successors and assigns of any of the above, all as and to the extent provided in this Agreement, and no other person shall acquire or have any right under or by virtue of this Agreement. The term “successors and assigns” shall not include a purchaser of any of the Shares from the Underwriters merely because of such purchase.

     Section 16. Partial Unenforceability. The invalidity or unenforceability of any Section, paragraph or provision of this Agreement shall not affect the validity or enforceability of any other Section, paragraph or provision hereof. If any Section, paragraph or provision of this Agreement is for any reason determined to be invalid or unenforceable, there shall be deemed to be made such minor changes (and only such minor changes) as are necessary to make it valid and enforceable.

     Section 17. Governing Law Provisions. THIS AGREEMENT SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK.

     Section 18. General Provisions. This Agreement constitutes the entire agreement of the parties to this Agreement and supersedes all prior written or oral and all contemporaneous oral agreements, understandings and negotiations with respect to the subject matter hereof. This Agreement may be executed in two or more counterparts, each one of which shall be an original, with the same effect as if the signatures thereto and hereto were upon the same instrument. This Agreement may not be amended or modified unless in writing by all of the parties hereto, and no condition herein (express or implied) may be waived unless waived in writing by each party whom the condition is meant to benefit. The section headings herein are for the convenience of the parties only and shall not affect the construction or interpretation of this Agreement.

     Each of the parties hereto acknowledges that it is a sophisticated business person who was adequately represented by counsel during negotiations regarding the provisions hereof, including, without limitation, the indemnification provisions of Section 8 and the contribution provisions of Section 9, and is fully informed regarding said provisions. Each of the parties hereto further acknowledges that the provisions of Sections 8 and 9 hereto fairly allocate the risks in light of the ability of the parties to investigate the Company, its affairs and its business in order to assure that adequate disclosure has been made in the Registration Statement, any preliminary prospectus and the Prospectus (and any amendments and supplements thereto), as required by the Securities Act and the Exchange Act.

     If the foregoing is in accordance with your understanding of our agreement, kindly sign and return to the Company the enclosed copies hereof, whereupon this instrument, along with all counterparts hereof, shall become a binding agreement in accordance with its terms.

     The foregoing Underwriting Agreement is hereby confirmed and accepted by the Representative as of the date first above written.

RBC CAPITAL MARKETS CORPORATION

     Acting as Representative of the several

     Underwriters named in the attached

     Schedule A.

By:		/s/ Joseph L Morea   Name: Joseph L. Morea
		Title: Managing Director

SCHEDULE A

		Number of Firm Shares to
Underwriters		be Purchased
RBC Capital Markets Corporation			3,300,000
Morgan Keegan & Company, Inc.			1,200,000
Johnson, Rice & Company L.L.C			1,200,000
Pritchard Capital Partners, LLC			300,000
Total			6,000,000

Sch. A

SCHEDULE B

Schedule of Free Writing Prospectuses

None

Sch B

SCHEDULE C

Number and Price of Shares

Public Offering Price		$	17.65
Underwriting Discounts		$	0.88250
Number of Shares being sold to the public			6,000,000
Proceeds to the Company before expenses		$	100,605,000

Sch C

SCHEDULE D

Securityholder Parties to Lock-Up Agreements

1.		Burt A. Adams
2.		Ali H. M. Afdhal
3.		David K. Bryan
4.		Alejandro P. Bulgheroni
5.		Carlos A. Bulgheroni
6.		Steven Collins
7.		James Davey
8.		Gary Edwards
9.		Jeffrey R. Freedman
10.		Victor F. Germack
11.		Munawar H. Hidayatallah
12.		Terrence P. Keane
13.		John E. McConnaughy, Jr.
14.		Robert E. Nederlander
15.		Victor M. Perez
16.		Theodore F. Pound III
17.		Bruce Sauers
18.		Leonard Toboroff

Sch D

SCHEDULE E

Name of Accountants		Name of Entity
UHY Mann Frankfort Stein & Lipp CPAs, LLP		Allis-Chalmers Energy Inc.
		Specialty Rental Tools, Inc.
UHY LLP		Allis-Chalmers Energy Inc.
		Oil & Gas Rental Services, Inc.
Gordon, Hughes and Banks, LLP		Allis-Chalmers Energy Inc.
Accounting & Consulting Group, LLP		W. T. Enterprises, Inc.
Wright, Moore, Dehart, Dupuis & Hutchinson, LLC		Delta Rental Service, Inc.
Curtis Blakely & Co., PC		Capcoil Tubing Services, Inc.
Sibille (la firma argentina miembro de KPMG		DLS Drilling, Logistics & Services Corporation
International, una cooperativa suiza)
Broussard, Poche, Lewis & Breaux, L.L.P.		Petro-Rentals, Inc.

Sch E

SCHEDULE F

     The Company’s Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2006 (the “Third Quarter 2006 Form 10-Q”), as originally filed with the Commission on November 8, 2006, did not include each of the following documents as exhibits thereto, each of which was subsequently filed with the Commission on December 29, 2006 as an exhibit to Amendment No. 1 on Form 10-Q/A to the Third Quarter 2006 Form 10-Q:

•		Strategic Agreement dated July 1, 2003 (the “Strategic Agreement”) between Pan American Energy LLC Sucursal Argentina and DLS Argentina Limited Sucursal Argentina;
•		Amendment No. 1 dated May 18, 2005 to the Strategic Agreement; and
•		Amendment No. 2 dated January 1, 2006 to the Strategic Agreement

Sch F

EXHIBIT A

Form of Opinion of Counsel for the Company

Exh. A

EXHIBIT B

[Date]

RBC Capital Markets Corporation
One Liberty Plaza
New York, New York 10006
      As Representative of the Several Underwriters

Re: Allis-Chalmers Energy Inc. (the “Company”)

Ladies and Gentlemen:

          The undersigned is an owner of record or beneficially of certain shares of Common Stock of the Company (“Common Stock”) or securities convertible into or exchangeable or exercisable for Common Stock. The Company proposes to carry out a public offering of Common Stock (the “Offering”) for which you will act as the representative (the “Representative”) of the syndicate of underwriters. The undersigned recognizes that the Offering will be of benefit to the undersigned and will benefit the Company. The undersigned acknowledges that you are relying on the representations and agreements of the undersigned contained in this letter in carrying out the Offering and in entering into underwriting arrangements with the Company with respect to the Offering.

          In consideration of the foregoing, the undersigned hereby agrees that the undersigned will not, (and will cause any spouse or immediate family member of the spouse or the undersigned living in the undersigned’s household not to), without your prior written consent (which consent may be withheld in its sole discretion), directly or indirectly, sell, offer, contract or grant any option to sell (including without limitation any short sale), pledge, transfer, establish an open “put equivalent position” or liquidate or decrease a “call equivalent position” within the meaning of Rule 16a-1(h) under the Securities Exchange Act of 1934, as amended, or otherwise dispose of or transfer (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition of) including the filing (or participation in the filing of) of a registration statement with the Shares and Exchange Commission in respect of, any shares of Common Stock, options or warrants to acquire shares of Common Stock, or securities exchangeable or exercisable for or convertible into shares of Common Stock currently or hereafter owned either of record or beneficially (as

Exh. B-1

defined in Rule 13d-3 under the Securities Exchange Act of 1934, as amended) by the undersigned (or such spouse or family member), or publicly announce an intention to do any of the foregoing, for a period commencing on the date hereof and continuing through the close of trading on the date 90 days after the date of the Prospectus (the “Lock-Up Period”). In addition, the undersigned agrees that, without your prior written consent, it will not, during the Lock-Up Period, make any demand for or exercise any right with respect to, the registration of any shares of Common Stock or any security convertible into or exercisable or exchangeable for Common Stock.

          If (i) the Company issues an earnings release or material news, or a material event relating to the Company occurs, during the last 17 days of the lock-up period, or (ii) prior to the expiration of the lock-up period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the lock-up period, the restrictions imposed by this agreement shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event, unless you waive, in writing, such extension; provided, however, that such restrictions shall not be so extended solely by virtue of the publishing or distribution by any Underwriter of any research regarding any earnings release, material news or a material event, if such research report complies with Rule 139 of the Securities Act and the Common Stock is “actively traded,” as defined in Rule 101(c)(1) of Regulation M under the Exchange Act. The undersigned hereby acknowledges that the Company has agreed in the Underwriting Agreement to provide written notice of any event that would result in an extension of the Lock-Up Period pursuant to the previous paragraph to the undersigned (in accordance with Section 14 of the Underwriting Agreement) and agrees that any such notice properly delivered will be deemed to have given to, and received by, the undersigned. The undersigned hereby further agrees that, prior to engaging in any transaction or taking any other action that is subject to the terms of this Lock-Up Agreement during the period from the date of this Lock-Up Agreement to and including the 34th day following the expiration of the initial Lock-Up Period, it will give notice thereof to the Company and will not consummate such transaction or take any such action unless it has received written confirmation from the Company that the Lock-Up Period (as such may have been extended pursuant to the previous paragraph) has expired. The undersigned also agrees and consents to the entry of stop transfer instructions with the Company’s transfer agent and registrar against the transfer of shares of Common Stock or securities convertible into or exchangeable or exercisable for Common Stock held by the undersigned except in compliance with the foregoing restrictions.

          With respect to the Offering only, the undersigned waives any registration rights relating to registration under the Securities Act of any Common Stock owned either of record or beneficially by the undersigned, including any rights to receive notice of the Offering.

Exh. B-2

     This agreement is irrevocable and will be binding on the undersigned and the respective successors, heirs, personal representatives, and assigns of the undersigned.

Printed Name of Holder

Printed Name of Person Signing

(and indicate capacity of person signing if

signing as custodian, trustee, or on behalf of an

entity)

Exh. B-3

ANNEX A

SUBSIDIARIES OF THE COMPANY

Name		Jurisdiction of Organization
Allis-Chalmers GP, LLC		Delaware
Allis-Chalmers LP, LLC		Delaware
Allis-Chalmers Management LP		Texas
Allis-Chalmers Production Services, Inc.		Texas
Allis-Chalmers Rental Services, Inc.		Texas
Allis-Chalmers Tubular Services, Inc.		Texas
Aircomp, L.L.C.		Delaware
DLS Drilling, Logistics & Services Corporation		British Virgin Islands
DLS Argentina Limited		British Virgin Islands
Mountain Compressed Air Inc.		Texas
OilQuip Rentals, Inc.		Delaware
Petro-Rentals, Incorporated		Louisiana
Strata Directional Technology, Inc.		Texas

Annex A-1