U.S. AUTO PARTS NETWORK, INC. INVESTORS RIGHTS AGREEMENT

Exhibit 10.6

U.S. AUTO PARTS NETWORK, INC.

INVESTORS’ RIGHTS AGREEMENT

March 3, 2006

TABLE OF CONTENTS

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U.S. AUTO PARTS NETWORK, INC.

INVESTORS’ RIGHTS AGREEMENT

This Investors’ Rights Agreement (this “Agreement”) is made as of March 3, 2006, by and among U.S. Auto Parts Network, Inc., a Delaware corporation (the “Company”), and Oak Investment Partners XI, Limited Partnership, a Delaware limited partnership (the “Investor”). Unless otherwise defined herein, capitalized terms used in this Agreement have the meanings ascribed to them in Section 1.

RECITALS

WHEREAS: The Investors are parties to the Series A Preferred Stock Purchase Agreement of even date herewith, among the Company, the Investor and the other parties named therein (the “Purchase Agreement”), and it is a condition to the closing of the sale of the Series A Preferred Stock to the Investor that the Investors and the Company execute and deliver this Agreement.

NOW, THEREFORE: In consideration of the mutual promises and covenants set forth herein, and other consideration, the receipt and adequacy of which is hereby acknowledged, the parties hereto agree as follows:

Section 1

Definitions

1.1 Certain Definitions. As used in this Agreement, the following terms shall have the meanings set forth below:

(a) “Commission” shall mean the Securities and Exchange Commission or any other federal agency at the time administering the Securities Act.

(b) “Common Stock” means the common stock of the Company.

(c) “Conversion Stock” shall mean shares of Common Stock issued upon conversion of the Series A Preferred Stock.

(d) “Convertible Securities” shall have the meaning assigned to such term in the Restated Certificate.

(e) “Deemed Liquidation” shall have the meaning assigned to such term in the Restated Certificate.

(f) “Exchange Act” shall mean the Securities Exchange Act of 1934, as amended, or any similar successor federal statute and the rules and regulations thereunder, all as the same shall be in effect from time to time.

(g) “Holder” shall mean any Investor who holds Registrable Securities and any holder of Registrable Securities to whom the registration rights conferred by this Agreement have been duly and validly transferred in accordance with Section 2.12 of this Agreement.

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(h) “Indemnified Party” shall have the meaning set forth in Section 2.6(c) hereto.

(i) “Indemnifying Party” shall have the meaning set forth in Section 2.6(c) hereto.

(j) “Initial Closing” shall mean the date of the initial sale of shares of the Company’s Series A Preferred Stock pursuant to the Purchase Agreement.

(k) “Initial Public Offering” shall mean the closing of the Company’s first firm commitment underwritten public offering of the Company’s Common Stock registered under the Securities Act.

(l) “Initiating Holders” shall mean any Holder or Holders who in the aggregate hold more than fifty percent (50%) of the outstanding Registrable Securities.

(m) “Investors” shall mean the persons and entities (each, an “Investor” and collectively, the “Investors”) listed on Exhibit A.

(n) “New Securities” shall have the meaning set forth in Section 4.1(a) hereto.

(o) “Options” shall have the meaning assigned such term in the Restated Certificate.

(p) “Other Selling Stockholders” shall mean persons other than Holders who, by virtue of agreements with the Company, are entitled to include their Other Shares in certain registrations hereunder.

(q) “Other Shares” shall mean shares of Common Stock, other than Registrable Securities (as defined below) with respect to which registration rights have been granted.

(r) “Purchase Agreement” shall have the meaning set forth in the Recitals hereto.

(s) “Qualified Public Offering” means an Initial Public Offering in which all outstanding Series A Preferred Stock converts to Common Stock.

(t) “Registrable Securities” shall mean (i) shares of Common Stock issued or issuable pursuant to the conversion of the Shares and (ii) any Common Stock issued as a dividend or other distribution with respect to or in exchange for or in replacement of the shares referenced in (i) above; provided, however, that Registrable Securities shall not include any shares of Common Stock described in clause (i) or (ii) above which have previously been registered or which have been sold to the public either pursuant to a registration statement or Rule 144, or which have been sold in a private transaction in which the transferor’s rights under this Agreement are not validly assigned in accordance with this Agreement.

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(u) The terms “register,” “registered” and “registration” shall refer to a registration effected by preparing and filing a registration statement in compliance with the Securities Act and applicable rules and regulations thereunder, and the declaration or ordering of the effectiveness of such registration statement.

(v) “Registration Expenses” shall mean all expenses incurred in effecting any registration pursuant to this Agreement, including, without limitation, all registration, qualification, and filing fees, printing expenses, escrow fees, fees and disbursements of counsel for the Company, blue sky fees and expenses, and expenses of any regular or special audits incident to or required by any such registration, up to $10,000 per registration for one special counsel for the selling Holders, and the compensation of regular employees of the Company for time spent on registration-related activities. Registration Expenses shall not include Selling Expenses, fees and disbursements of other counsel for the Holders.

(w) “Restated Certificate” shall mean the Company’s Amended and Restated Certificate of Incorporation, as in effect at the time of the original issuance of Series A Preferred Stock to the Investor.

(x) “Restricted Securities” shall mean any Registrable Securities required to bear the first legend set forth in Section 2.8(c) hereof.

(y) “Rule 144” shall mean Rule 144 as promulgated by the Commission under the Securities Act, as such Rule may be amended from time to time, or any similar successor rule that may be promulgated by the Commission.

(z) “Rule 145” shall mean Rule 145 as promulgated by the Commission under the Securities Act, as such Rule may be amended from time to time, or any similar successor rule that may be promulgated by the Commission

(aa) “Rule 415” shall mean Rule 415 as promulgated by the Commission under the Securities Act, as such Rule may be amended from time to time, or any similar successor rule that may be promulgated by the Commission.

(bb) “Securities Act” shall mean the Securities Act of 1933, as amended, or any similar successor federal statute and the rules and regulations thereunder, all as the same shall be in effect from time to time.

(cc) “Selling Expenses” shall mean all underwriting discounts, selling commissions and stock transfer taxes applicable to the sale of Registrable Securities and fees and disbursements of counsel for any Holder (other than the fees and disbursements of one special counsel to the selling Holders included in Registration Expenses).

(dd) “Series A Preferred Stock” shall mean the shares of Series A Preferred Stock issued pursuant to the Purchase Agreement.

(ee) “Shares” shall mean the Company’s Series A Preferred Stock.

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(ff) “Significant Holders” shall have the meaning set forth in Section 3.1 hereof.

(gg) “Withdrawn Registration” shall mean a forfeited demand registration under Section 2.1 in accordance with the terms and conditions of Section 2.4.

Section 2

Registration Rights

2.1 Requested Registration.

(a) Request for Registration. Subject to the conditions set forth in this Section 2.1, if the Company shall receive from Initiating Holders a written request signed by such Initiating Holders that the Company effect any registration with respect to all or a part of the Registrable Securities (such request shall state the number of shares of Registrable Securities to be disposed of and the intended methods of disposition of such shares by such Initiating Holders), the Company will:

(i) promptly give written notice of the proposed registration to all other Holders; and

(ii) as soon as practicable, file and use good best efforts to effect such registration (including, without limitation, filing post-effective amendments, appropriate qualifications under applicable blue sky or other state securities laws, and appropriate compliance with the Securities Act) and to permit or facilitate the sale and distribution of all or such portion of such Registrable Securities as are specified in such request, together with all or such portion of the Registrable Securities of any Holder or Holders joining in such request as are specified in a written request received by the Company within twenty (20) days after such written notice from the Company is mailed or delivered.

(b) Limitations on Requested Registration. The Company shall not be obligated to effect, or to take any action to effect, any such registration pursuant to this Section 2.1:

(i) Prior to the earlier of (A) the 18-month anniversary of the date of this Agreement or (B) six months following the effective date of the Initial Public Offering;

(ii) If the Initiating Holders, together with the holders of any other securities of the Company entitled to inclusion in such registration statement, propose to sell Registrable Securities and such other securities (if any) at an aggregate offering price to the public of less than $10,000,000;

(iii) In any particular jurisdiction in which the Company would be required to execute a general consent to service of process in effecting such registration, qualification, or compliance, unless the Company is already subject to service in such jurisdiction and except as may be required by the Securities Act;

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(iv) After the Company has initiated two such registrations pursuant to this Section 2.1 (counting for these purposes only (x) registrations which have been declared or ordered effective and pursuant to which securities have been sold, and (y) Withdrawn Registrations);

(v) During the period starting with the date sixty (60) days prior to the Company’s good faith estimate of the date of filing of, and ending on a date one hundred eighty (180) days after the effective date of, a Company-initiated registration; provided that the Company is actively employing in good faith commercially reasonable efforts to cause such registration statement to become effective; or

(vi) If the Initiating Holders propose to dispose of shares of Registrable Securities which may be immediately registered on Form S-3 pursuant to a request made under Section 2.3 hereof.

(c) Deferral. If (i) in the good faith judgment of the Board of Directors of the Company, the filing of a registration statement covering the Registrable Securities would be materially detrimental to the Company and the Board of Directors of the Company concludes, as a result, that it is in the best interests of the Company to defer the filing of such registration statement at such time, and (ii) the Company shall furnish to such Holders a certificate signed by the President of the Company stating that in the good faith judgment of the Board of Directors of the Company, it would be materially detrimental to the Company for such registration statement to be filed in the near future and that it is, therefore, in the best interests of the Company to defer the filing of such registration statement, then (in addition to the limitations set forth in Section 2.1(b)(v) above) the Company shall have the right to defer such filing for a period of not more than ninety (90) days after receipt of the request of the Initiating Holders, and, provided further, that the Company shall not defer its obligation in this manner more than once in any twelve month period.

(d) Other Shares. The registration statement filed pursuant to the request of the Initiating Holders may, subject to the provisions of Section 2.1(e), include Other Shares, and may include securities of the Company being sold for the account of the Company.

(e) Underwriting. If the Initiating Holders intend to distribute the Registrable Securities covered by their request by means of an underwriting, they shall so advise the Company as a part of their request made pursuant to this Section 2.1 and the Company shall include such information in the written notice given pursuant to Section 2.1(a)(i). In such event, the right of any Holder to include all or any portion of its Registrable Securities in such registration pursuant to this Section 2.1 shall be conditioned upon such Holder’s participation in such underwriting and the inclusion of such Holder’s Registrable Securities to the extent provided herein. If the Company shall request inclusion in any registration pursuant to Section 2.1 of securities being sold for its own account, or if other persons shall request inclusion in any registration pursuant to Section 2.1, the Initiating Holders shall, on behalf of all Holders, offer to include such securities in the underwriting and such offer shall be conditioned upon the participation of the Company or such other persons in such underwriting and the inclusion of the Company’s and such person’s other securities of the Company and their acceptance of the further applicable provisions of this Section 2 (including Section 2.10). The Company shall (together

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with all Holders and other persons proposing to distribute their securities through such underwriting) enter into an underwriting agreement in customary form with the representative of the underwriter or underwriters selected for such underwriting by a majority in interest of the Initiating Holders, which underwriters are reasonably acceptable to the Company.

Notwithstanding any other provision of this Section 2.1, if the underwriters advise the Initiating Holders in writing that marketing factors require a limitation on the number of shares to be underwritten, the number of Registrable Securities and Other Shares that may be so included shall be allocated as follows: (i) first, among all Holders requesting to include Registrable Securities in such registration statement based on the pro rata percentage of Registrable Securities held by such Holders and Other Selling Stockholders; (ii) second, to the Other Selling Stockholders; and (iii) third, to the Company, which the Company may allocate, at its discretion, for its own account, or for the account of other holders or employees of the Company.

If a person who has requested inclusion in such registration as provided above does not agree to the terms of any such underwriting, such person shall be excluded therefrom by written notice from the Company, the underwriter or the Initiating Holders. The securities so excluded shall also be withdrawn from registration. Any Registrable Securities or other securities excluded or withdrawn from such underwriting shall also be withdrawn from such registration. If shares are so withdrawn from the registration and if the number of shares to be included in such registration was previously reduced as a result of marketing factors pursuant to this Section 2.1(e), then the Company shall then offer to all Holders who have retained rights to include securities in the registration the right to include additional Registrable Securities in the registration in an aggregate amount equal to the number of shares so withdrawn, with such shares to be allocated among such Holders requesting additional inclusion as set forth above.

2.2 Company Registration.

(a) Company Registration. If the Company shall determine to register any of its securities either for its own account or the account of a security holder or holders, other than a registration pursuant to Section 2.1 or 2.3, a registration relating solely to employee benefit plans, a registration relating to the offer and sale of debt securities, a registration relating to a corporate reorganization or other Rule 145 transaction, or a registration on any registration form that does not permit secondary sales, the Company will:

(i) promptly give written notice of the proposed registration to all Holders; and

(ii) use good faith commercially reasonable efforts to include in such registration (and any related qualification under blue sky laws or other compliance), except as set forth in Section 2.2(b) below, and in any underwriting involved therein, all of such Registrable Securities as are specified in a written request or requests made by any Holder or Holders received by the Company within ten (10) days after such written notice from the Company is mailed or delivered. Such written request may specify all or a part of a Holder’s Registrable Securities.

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(b) Underwriting. If the registration of which the Company gives notice is for a registered public offering involving an underwriting, the Company shall so advise the Holders as a part of the written notice given pursuant to Section 2.2(a)(i). In such event, the right of any Holder to registration pursuant to this Section 2.2 shall be conditioned upon such Holder’s participation in such underwriting and the inclusion of such Holder’s Registrable Securities in the underwriting to the extent provided herein. All Holders proposing to distribute their securities through such underwriting shall (together with the Company and the Other Selling Stockholders other holders of securities of the Company with registration rights to participate therein distributing their securities through such underwriting) enter into an underwriting agreement in customary form with the representative of the underwriter or underwriters selected by the Company.

Notwithstanding any other provision of this Section 2.2, if the underwriters advise the Company in writing that marketing factors require a limitation on the number of shares to be underwritten, the underwriters may (subject to the limitations set forth below) limit the number of Registrable Securities to be included in, the registration and underwriting subject to the limitation in Section 2.2(a)(ii). The Company shall so advise all holders of securities requesting registration, and the number of shares of securities that are entitled to be included in the registration and underwriting shall be allocated, as follows: (i) first, to the Company for securities being sold for its own account, (ii) second, to the Holders requesting to include Registrable Securities in such registration statement based on the pro rata percentage of Registrable Securities held by such Holders, and (iii) third, to the Other Selling Stockholders requesting to include Other Shares in such registration statement based on the pro rata percentage of Other Shares held by such Other Selling Stockholders, assuming conversion. Notwithstanding the foregoing, in no event shall the number of Registrable Securities included in such registration be reduced below 20% of the total number of shares included in such registration, except in case of a Qualified Public Offering, in which case the number of Registrable Securities included in such registration may be reduced to zero pursuant to this paragraph.

If a person who has requested inclusion in such registration as provided above does not agree to the terms of any such underwriting, such person shall also be excluded therefrom by written notice from the Company or the underwriter. The Registrable Securities or other securities so excluded shall also be withdrawn from such registration. Any Registrable Securities or other securities excluded or withdrawn from such underwriting shall be withdrawn from such registration. If shares are so withdrawn from the registration and if the number of shares of Registrable Securities to be included in such registration was previously reduced as a result of marketing factors pursuant to Section 2.2(b), the Company shall then offer to all persons who have retained the right to include securities in the registration the right to include additional securities in the registration in an aggregate amount equal to the number of shares so withdrawn, with such shares to be allocated among the persons requesting additional inclusion, in the manner set forth above.

(c) Right to Terminate Registration. The Company shall have the right to terminate or withdraw any registration initiated by it under this Section 2.2 prior to the effectiveness of such registration whether or not any Holder has elected to include securities in such registration.

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2.3 Registration on Form S-3.

(a) Request for Form S-3 Registration. After the Company becomes subject to the reporting obligations of Section 13 of the Exchange Act, the Company shall use good faith commercially reasonable efforts to qualify for registration on Form S-3 or any comparable or successor form or forms. After the Company has qualified for the use of Form S-3, in addition to the rights contained in the foregoing provisions of this Section 2 and subject to the conditions set forth in this Section 2.3, if the Company shall receive from a Holder or Holders of Registrable Securities a written request that the Company effect any registration on Form S-3 or any similar short form registration statement with respect to all or part of the Registrable Securities (such request shall state the number of shares of Registrable Securities to be disposed of and the intended methods of disposition of such shares by such Holder or Holders), the Company will take all such action with respect to such Registrable Securities as required by Section 2.1(a)(i) and (ii).

(b) Limitations on Form S-3 Registration. The Company shall not be obligated to effect, or take any action to effect, any such registration pursuant to this Section 2.3:

(i) In the circumstances described in either Sections 2.1(b)(i), 2.1(b)(iii) or 2.1(b)(v);

(ii) If the Holders, together with the holders of any other securities of the Company entitled to inclusion in such registration, propose to sell Registrable Securities and such other securities (if any) on Form S-3 at an aggregate price to the public of less than $5,000,000; or

(iii) If, in a given twelve-month period, the Company has effected two (2) such registrations in such period.

(c) Deferral. The provisions of Section 2.1(c) shall apply to any registration pursuant to this Section 2.3.

(d) Underwriting. If the Holders of Registrable Securities requesting registration under this Section 2.3 intend to distribute the Registrable Securities covered by their request by means of an underwriting, the provisions of Sections 2.1(e) shall apply to such registration. Notwithstanding anything contained herein to the contrary, registrations effected pursuant to this Section 2.3 shall not be counted as requests for registration or registrations effected pursuant to Section 2.1.

2.4 Expenses of Registration. All Registration Expenses incurred in connection with registrations pursuant to Sections 2.1, 2.2 and 2.3 hereof shall be borne by the Company; provided, however, that the Company shall not be required to pay for any expenses of any registration proceeding begun pursuant to Sections 2.1 and 2.3 if the registration request is subsequently withdrawn at the request of the Holders of a majority of the Registrable Securities to be registered or because a sufficient number of Holders shall have withdrawn so that the minimum offering conditions set forth in Sections 2.1 and 2.3 are no longer satisfied (in which case all participating Holders shall bear such expenses pro rata among each other based on the number of Registrable Securities requested to be so registered), unless the Holders of a majority

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of the Registrable Securities agree to forfeit their right to a demand registration pursuant to Section 2.1; provided, however, in the event that a withdrawal by the Holders is based upon material adverse information relating to the Company that is different from the information known or available (upon request from the Company or otherwise) to the Holders requesting registration at the time of their request for registration under Section 2.1, such registration shall not be treated as a counted registration for purposes of Section 2.1 hereof, even though the Holders do not bear the Registration Expenses for such registration. All Selling Expenses relating to securities registered on behalf of the Holders shall be borne by the holders of securities included in such registration pro rata among each other on the basis of the number of Registrable Securities so registered.

2.5 Registration Procedures. In the case of each registration effected by the Company pursuant to Section 2, the Company will keep each Holder advised in writing as to the initiation of each registration and as to the completion thereof. At its expense, the Company will use good faith commercially reasonable efforts to:

(a) Keep such registration effective for a period of ending on the earlier of the date which is one hundred twenty (120) days from the effective date of the registration statement or such time as the Holder or Holders have completed the distribution described in the registration statement relating thereto;

(b) Prepare and file with the Commission such amendments and supplements to such registration statement and the prospectus used in connection with such registration statement as may be necessary to comply with the provisions of the Securities Act with respect to the disposition of all securities covered by such registration statement for the period set forth in subsection (a) above;

(c) Furnish such number of prospectuses, including any preliminary prospectuses, and other documents incident thereto, including any amendment of or supplement to the prospectus, as a Holder from time to time may reasonably request;

(d) Register and qualify the securities covered by such registration statement under such other securities or blue sky laws of such jurisdiction as shall be reasonably requested by the Holders; provided, that the Company shall not be required in connection therewith or as a condition thereto to qualify to do business or to file a general consent to service of process in any such states or jurisdictions unless the Company is already subject to service in such jurisdiction and except as may be required by the Securities Act;

(e) Notify each seller of Registrable Securities covered by such registration statement at any time when a prospectus relating thereto is required to be delivered under the Securities Act of the happening of any event as a result of which the prospectus included in such registration statement, as then in effect, includes an untrue statement of a material fact or omits to state a material fact required to be stated therein or necessary to make the statements therein not misleading or incomplete in light of the circumstances then existing, and following such notification promptly prepare and furnish to such seller a reasonable number of copies of a supplement to or an amendment of such prospectus as may be necessary so that, as thereafter delivered to the purchasers of such shares, such prospectus shall not include an untrue statement

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of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading or incomplete in light of the circumstances then existing;

(f) Furnish, on the date that such Registrable Securities are delivered to the underwriters for sale, if such securities are being sold through underwriters, (i) an opinion, dated as of such date, of the counsel representing the Company for the purposes of such registration, in form and substance as is customarily given to underwriters in an underwritten public offering, addressed to the underwriters, if any, and reasonably satisfactory to a majority in interest of the Holders requesting registration of Registrable Securities and (ii) a “comfort” letter dated as of such date, from the independent certified public accountants of the Company, in form and substance as is customarily given by independent certified public accountants to underwriters in an underwritten public offering, addressed to the underwriters;

(g) Provide a transfer agent and registrar for all Registrable Securities registered pursuant to such registration statement and a CUSIP number for all such Registrable Securities, in each case not later than the effective date of such registration;

(h) Comply with all applicable rules and regulations of the Commission, and make available to its security holders, as soon as reasonably practicable, an earnings statement covering the period of at least twelve months, but not more than eighteen months, beginning with the first month after the effective date of the Registration Statement, which earnings statement shall satisfy the provisions of Section 11(a) of the Securities Act;

(i) Cause all such Registrable Securities registered pursuant hereunder to be listed on each securities exchange on which similar securities issued by the Company are then listed; and

(j) In connection with any underwritten offering pursuant to a registration statement filed pursuant to Section 2.1 hereof, enter into an underwriting agreement in form reasonably necessary to effect the offer and sale of Common Stock, provided such underwriting agreement contains reasonable and customary provisions, and provided further, that each Holder participating in such underwriting shall also enter into and perform its obligations under such an agreement.

2.6 Indemnification.

(a) To the extent permitted by law, the Company will indemnify and hold harmless each Holder, each of its officers, directors, agents and employees and each person controlling such Holder within the meaning of Section 15 of the Securities Act, with respect to which registration, qualification, or compliance has been effected pursuant to this Section 2, and each underwriter, if any, of the Registrable Shares and each person who controls within the meaning of Section 15 of the Securities Act any such underwriter, against all expenses, claims, losses, damages, and liabilities (or actions, proceedings, or settlements in respect thereof) arising out of or based on: (i) any untrue statement (or alleged untrue statement) of a material fact contained or incorporated by reference in any prospectus, offering circular, or other document (including any related registration statement, notification, or the like) incident to any such

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registration, qualification, or compliance, (ii) any omission (or alleged omission) to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, or (iii) any violation (or alleged violation) by the Company of the Securities Act, any state securities laws or any rule or regulation thereunder applicable to the Company and relating to action or inaction required of the Company in connection with any offering covered by such registration, qualification, or compliance, and the Company will reimburse each such Holder, each of its officers, directors, agents and employees and each person controlling such Holder, each such underwriter, and each person who controls any such underwriter, for any legal and any other expenses reasonably incurred in connection with investigating and defending or settling any such claim, loss, damage, liability, or action; provided that the Company will not be liable in any such case to the extent that any such claim, loss, damage, liability, or action arises out of or is based on any untrue statement or omission based upon written information furnished to the Company by such Holder, any of such Holder’s officers, directors, agents and employees, any person controlling such Holder, such underwriter or any person who controls any such underwriter and stated to be specifically for use therein; and provided, further that, the indemnity agreement contained in this Section 2.6(a) shall not apply to (x) in the case of a sale directly by such holder of Registrable Shares (including a sale of such Registrable Shares through any underwriter retained by such holder of Registrable Shares to engage in a distribution solely on behalf of such holder of Registrable Shares), such untrue statement or alleged untrue statement or omission or alleged omission was contained in a preliminary prospectus and corrected in a final or amended prospectus, and (A) such holder of Registrable Shares (or underwriter) failed to deliver a copy of the final or amended prospectus at or prior to the confirmation of the sale of the Registrable Shares to the person asserting any such loss, claim, damage or liability in any case where such delivery is required by the Securities Act or any state securities laws and (B) the Company complied with its obligations under Section 2.5 hereunder with respect to such final or amended prospectus, or (y) amounts paid in settlement of any such loss, claim, damage, liability, or action if such settlement is effected without the consent of the Company (which consent shall not be unreasonably withheld).

(b) To the extent permitted by law, each Holder will, if Registrable Securities held by such Holder are included in the securities as to which such registration, qualification, or compliance is being effected, indemnify and hold harmless the Company, each of its directors, officers, agents and employees, and each underwriter, if any, of the Company’s securities covered by such a registration statement, each person who controls the Company or such underwriter within the meaning of Section 15 of the Securities Act, each other such Holder, and each of their officers, directors, and partners, and each person controlling such Holder, against all claims, losses, damages and liabilities (or actions in respect thereof) arising out of or based on: (i) any untrue statement (or alleged untrue statement) of a material fact contained or incorporated by reference in any such registration statement, prospectus, offering circular, or other document, or (ii) any omission (or alleged omission) to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, and will reimburse the Company and such Holders, directors, officers, partners, legal counsel, and accountants, persons, underwriters, or control persons for any legal or any other expenses reasonably incurred in connection with investigating or defending any such claim, loss, damage, liability, or action, in each case to the extent, but only to the extent, that such untrue statement (or alleged untrue statement) or omission (or alleged omission) is made in such registration statement, prospectus, offering circular, or other document in reliance upon and in conformity with written information

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furnished to the Company by such Holder and stated to be specifically for use therein; provided, however, that the obligations of such Holder hereunder shall not apply to amounts paid in settlement of any such claims, losses, damages, or liabilities (or actions in respect thereof) if such settlement is effected without the consent of such Holder (which consent shall not be unreasonably withheld) unless such settlement includes as an unconditional term thereof the giving by the claimant or plaintiff to such Holder of a release from all liability in respect to such claim or litigation; and provided that in no event shall any indemnity under this Section 2.6 exceed the net proceeds from the offering received by such Holder.

(c) Each party entitled to indemnification under this Section 2.6 (the “Indemnified Party”) shall give notice to the party required to provide indemnification (the “Indemnifying Party”) promptly after such Indemnified Party has actual knowledge of any claim as to which indemnity may be sought, and shall permit the Indemnifying Party to assume the defense of such claim or any litigation resulting therefrom; provided that counsel for the Indemnifying Party, who shall conduct the defense of such claim or any litigation resulting therefrom, shall be approved by the Indemnified Party (whose approval shall not be unreasonably withheld), and the Indemnified Party may participate in such defense at such party’s expense; and provided further that the failure of any Indemnified Party to give notice as provided herein shall not relieve the Indemnifying Party of its obligations under this Section 2.6, to the extent such failure is not prejudicial. No Indemnifying Party, in the defense of any such claim or litigation, shall, except with the consent of each Indemnified Party, consent to entry of any judgment or enter into any settlement that does not include as an unconditional term thereof the giving by the claimant or plaintiff to such Indemnified Party of a release from all liability in respect to such claim or litigation. Each Indemnified Party shall furnish such information regarding itself or the claim in question as an Indemnifying Party may reasonably request in writing and as shall be reasonably required in connection with defense of such claim and litigation resulting therefrom.

(d) If the indemnification provided for in this Section 2.6 is held by a court of competent jurisdiction to be unavailable to an Indemnified Party with respect to any loss, liability, claim, damage, or expense referred to herein, then the Indemnifying Party, in lieu of indemnifying such Indemnified Party hereunder, shall contribute to the amount paid or payable by such Indemnified Party as a result of such loss, liability, claim, damage, or expense in such proportion as is appropriate to reflect the relative fault of the Indemnifying Party on the one hand and of the Indemnified Party on the other in connection with the statements or omissions that resulted in such loss, liability, claim, damage, or expense as well as any other relevant equitable considerations. The relative fault of the Indemnifying Party and of the Indemnified Party shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission to state a material fact relates to information supplied by the Indemnifying Party or by the Indemnified Party and the parties’ relative intent, knowledge, access to information, and opportunity to correct or prevent such statement or omission. In no event shall any contribution by a Holder under this Section 2.6(d), when aggregated by any indemnity paid by such Holder under this Section 2.6, exceed the net proceeds from the offering received by such Holder.

(e) Notwithstanding the foregoing, to the extent that the provisions on indemnification and contribution contained in the underwriting agreement entered into in

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connection with the underwritten public offering are in conflict with the foregoing provisions, the provisions in the underwriting agreement shall control.

2.7 Information by Holder. Each Holder of Registrable Securities shall furnish to the Company such information regarding such Holder and the distribution proposed by such Holder as the Company may reasonably request in writing and as shall be reasonably required in connection with any registration, qualification, or compliance referred to in this Section 2. Any such information so provided by such Holder, including any such information regarding such Holder’s plan of distribution, included in any prospectus, offering circular, or other document (including any related registration statement, notification, or the like) incident to any such registration, qualification, or compliance shall be considered for purposes of Sections 2.6(a) and (b) written information furnished to the Company by such Holder that is stated to be specifically for use in any prospectus, offering circular, or other document (including any related registration statement, notification, or the like) incident to any such registration, qualification, or compliance.

2.8 Restrictions on Transfer.

(a) The holder of each certificate representing Registrable Securities by acceptance thereof agrees to comply in all respects with the provisions of this Section 2.8. Each Holder agrees not to make any sale, assignment, transfer, pledge or other disposition of all or any portion of the Restricted Securities, or any beneficial interest therein, unless and until, (x) other than in connection with sales pursuant to an effective registration statement or sales or transfers pursuant to Rule 144, the transferee thereof has agreed in writing for the benefit of the Company to take and hold such Restricted Securities subject to, and to be bound by, the terms and conditions set forth in this Agreement, including, without limitation, this Section 2.8 and Section 2.10, and, (y) except with respect to permitted transfers under Section 2.8(b):

(i) There is then in effect a registration statement under the Securities Act covering such proposed disposition and such disposition is made in accordance with such registration statement; or

(ii) Such Holder shall have given prior written notice to the Company of such Holder’s intention to make such disposition and shall have furnished the Company with a detailed description of the manner and circumstances of the proposed disposition, and, if requested by the Company, such Holder shall have furnished the Company, at its expense, with an opinion of counsel, reasonably satisfactory to the Company, to the effect that such disposition will not require registration of such Restricted Securities under the Securities Act.

(b) Permitted transfers include (i) a transfer not involving a change in beneficial ownership, or (ii) in transactions involving the distribution without consideration of Restricted Securities by any Holder to (x) a parent, subsidiary or other affiliate of Holder that is a Corporation, or (y) any of its partners, members or other equity owners, or retired partners, retired members or other equity owners, or to the estate of any of its partners, members or other equity owners or retired partners, retired members or other equity owners, or (iii) transfers in compliance with Rule 144(k), as long as the Company is furnished with satisfactory evidence of compliance with such Rule; provided, in each case, that the Holder thereof shall give written notice to the Company of such Holder’s intention to effect such disposition and shall have

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furnished the Company with a detailed description of the manner and circumstances of the proposed disposition.

(c) Each certificate representing Registrable Securities shall (unless otherwise permitted by the provisions of this Agreement) be stamped or otherwise imprinted with a legend substantially similar to the following (in addition to any legend required under applicable state securities laws):

THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”), OR UNDER THE SECURITIES LAWS OF CERTAIN STATES. THESE SECURITIES MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED EXCEPT AS PERMITTED UNDER THE ACT AND APPLICABLE STATE SECURITIES LAWS PURSUANT TO REGISTRATION OR AN EXEMPTION THEREFROM. THE ISSUER OF THESE SECURITIES MAY REQUIRE AN OPINION OF COUNSEL SATISFACTORY TO THE ISSUER THAT SUCH OFFER, SALE OR TRANSFER, PLEDGE OR HYPOTHECATION OTHERWISE COMPLIES WITH THE ACT AND ANY APPLICABLE STATE SECURITIES LAWS.

THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO (1) RESTRICTIONS ON TRANSFERABILITY AND RESALE, INCLUDING A LOCK-UP PERIOD OF UP TO 180 DAYS IN THE EVENT OF A PUBLIC OFFERING, AS SET FORTH IN AN INVESTOR RIGHTS AGREEMENT, AND (2) VOTING RESTRICTIONS AS SET FORTH IN A VOTING AGREEMENT AMONG THE COMPANY AND THE ORIGINAL HOLDERS OF THESE SHARES, COPIES OF WHICH MAY BE OBTAINED AT THE PRINCIPAL OFFICE OF THE COMPANY.

The Holders consent to the Company making a notation on its records and giving instructions to any transfer agent of the Restricted Securities in order to implement the restrictions on transfer established in this Section 2.8.

(d) The first legend referring to federal and state securities laws identified in Section 2.8(c) hereof stamped on a certificate evidencing the Restricted Securities and the stock transfer instructions and record notations with respect to such Restricted Securities shall be removed and the Company shall issue a certificate without such legend to the holder of such Restricted Securities if (i) such securities are registered under the Securities Act, or (ii) such holder provides the Company with an opinion of counsel reasonably acceptable to the Company to the effect that a public sale or transfer of such securities may be made without registration under the Securities Act, or (iii) such holder provides the Company with reasonable assurances, which may, at the option of the Company, include an opinion of counsel satisfactory to the Company, that such securities can be sold pursuant to Section (k) of Rule 144 under the Securities Act.

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2.9 Rule 144 Reporting. With a view to making available the benefits of certain rules and regulations of the Commission that may permit the sale of the Restricted Securities to the public without registration, the Company agrees to use good faith commercially reasonable efforts to:

(a) Make and keep public information regarding the Company available as those terms are understood and defined in Rule 144 under the Securities Act, at all times from and after ninety (90) days following the effective date of the first registration under the Securities Act filed by the Company for an offering of its securities to the general public;

(b) File with the Commission in a timely manner all reports and other documents required of the Company under the Securities Act and the Exchange Act after it has become subject to such reporting requirements, for so long as the Company remains subject to such reporting requirements; and

(c) So long as a Holder owns any Restricted Securities and the Company remains subject to the reporting requirements of the Securities Act and the Exchange Act, furnish to the Holder forthwith upon written request a written statement by the Company as to its compliance with the reporting requirements of Rule 144 (at any time from and after ninety (90) days following the effective date of the first registration statement filed by the Company for an offering of its securities to the general public), and of the Securities Act and the Exchange Act (at any time after it has become subject to such reporting requirements), a copy of the most recent annual or quarterly report of the Company, and such other reports and documents so filed as a Holder may reasonably request in availing itself of any rule or regulation of the Commission allowing a Holder to sell any such securities without registration.

2.10 Market Stand-Off Agreement. Each Holder hereby agrees that such Holder shall not sell or otherwise transfer, make any short sale of, grant any option for the purchase of, or enter into any hedging or similar transaction with the same economic effect as a sale, of any Common Stock (or other securities) of the Company held by such Holder (other than those included in the registration) during a period as requested by the Company (not to exceed one hundred eighty (180) days) following the effective date of the Company’s Initial Public Offering, provided that: (i) all officers and directors of the Company and holders of at least one percent (1%) of the Company’s voting securities are bound by and have entered into similar agreements and (ii) such agreement shall provide that any discretionary waiver or termination of the restrictions of such agreements by the Company or underwriters shall apply to all persons pro rata based on the number of shares of Common Stock subject to such agreements. The obligations described in this Section 2.10 shall not apply to a registration relating solely to employee benefit plans on Form S-1 or Form S-8 or similar forms that may be promulgated in the future, or a registration relating solely to a transaction on Form S-4 or similar forms that may be promulgated in the future. The Company may impose stop-transfer instructions and may stamp each such certificate with the second legend set forth in Section 2.8(c) hereof with respect to the shares of Common Stock (or other securities) subject to the foregoing restriction until the end of such one hundred eighty (180) day period. If requested by the Company and an underwriter of Common Stock (or other securities) of the Company, each Holder agrees to execute a market standoff agreement with said underwriters in customary form consistent with the provisions of this Section 2.10.

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2.11 Delay of Registration. No Holder shall have any right to take any action to restrain, enjoin, or otherwise delay any registration as the result of any controversy that might arise with respect to the interpretation or implementation of this Section 2.

2.12 Transfer or Assignment of Registration Rights. The rights to cause the Company to register securities granted to a Holder by the Company under this Section 2 may be transferred or assigned by a Holder only to a transferee or assignee (i) of not less than 100,000 shares of Registrable Securities (as presently constituted and subject to subsequent adjustments for stock splits, stock dividends, reverse stock splits, and the like) or (ii) to a partner, retired partner, member, retired member or affiliate of the Holder (without restriction as to minimum share holdings); provided that (a) such transfer or assignment of Registrable Securities is effected in accordance with the terms of Section 2.8 hereof and applicable securities laws, (b) the Company is given written notice prior to said transfer or assignment, stating the name and address of the transferee or assignee and identifying the securities with respect to which such registration rights are intended to be transferred or assigned and (c) the transferee or assignee of such rights assumes in writing the obligations of such Holder under this Agreement, including without limitation the obligations set forth in Section 2.10.

2.13 Limitations on Subsequent Registration Rights. From and after the date of this Agreement, the Company shall not, without the prior written consent of a majority in interest of the Holders, enter into any agreement with any holder or prospective holder of any securities of the Company giving such holder or prospective holder any registration rights the terms of which are pari passu with or senior to the registration rights granted to the Holders hereunder; provided, however, (i) without such consent, at any time after the consummation of the Initial Public Offering, the Company may enter into an agreement with any holder or prospective holder of any securities of the Company giving such holder or prospective holder any registration rights the terms of which are pari passu with the registration rights granted to the Holders hereunder, (ii) at any time after the date that is two years after consummation of the Initial Public Offering, this Section 2.13 will not apply to any such agreements with any holder or prospective holder of any securities of the Company, and (iii) this Section 2.13 will terminate at such time as all Holders’ registration rights have terminated pursuant to Section 2.14. Further, the Company agrees to use best efforts to ensure that all future issuances of capital stock shall be subject to a market stand off provision at least as restrictive as those set forth in Section 2.10.

2.14 Termination of Registration Rights. The right of any Holder to request registration or inclusion in any registration pursuant to Section 2.1, 2.2 or 2.3 shall terminate on the earlier of, (i) with respect to any Holder, on such date, on or after the closing of the Company’s first registered public offering of Common Stock, on which all shares of Registrable Securities held or entitled to be held upon conversion by such Holder total, the aggregate, less than 1% of the outstanding shares of Common Stock of the Company and such Holder receives an opinion of counsel, reasonably acceptable to such Holder, that such Holder can sell all of its shares immediately under Rule 144(k), and (ii) five (5) years after the closing of the Company’s Initial Public Offering.

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Section 3

Additional Covenants of the Company

The Company hereby covenants and agrees, as follows:

3.1 Basic Financial Information and Inspection Rights.

(a) Basic Financial Information. The Company will furnish the following reports to the Investor and each Holder who, with its affiliates, owns at least 2,000,000 shares of Series A Preferred Stock (as presently constituted and subject to subsequent adjustments for stock splits, stock dividends, reverse stock splits, and the like) (each, a “Significant Holder”):

(i) As soon as practicable after the end of each fiscal year of the Company, and in any event within one hundred twenty (120) days after the end of each fiscal year of the Company, a consolidated balance sheet of the Company and its subsidiaries, if any, as at the end of such fiscal year, and consolidated statements of income and cash flows of the Company and its subsidiaries, if any, for such year, prepared in accordance with U.S. generally accepted accounting principles consistently applied, certified by independent public accountants of recognized national standing selected by the Company and certified by the Chief Financial Officer of the Company;

(ii) As soon as practicable after the end of the first, second and third quarterly accounting periods in each fiscal year of the Company, and in any event within forty-five (45) days after the end of the first, second, and third quarterly accounting periods in each fiscal year of the Company, an unaudited consolidated balance sheet of the Company and its subsidiaries, if any, as of the end of each such quarterly period, and unaudited consolidated statements of income and cash flows of the Company and its subsidiaries, if any, for such period, prepared in accordance with U.S. generally accepted accounting principles consistently applied, subject to changes resulting from normal year-end audit adjustments;

(iii) As soon as practicable after the end of each fiscal year of the Company, and in any event within sixty (60) days after the end of each fiscal year of the Company, an annual budget and business plan.

3.2 Inspection Rights. The Company will afford to each Significant Holder and to such Significant Holder’s accountants and counsel, upon prior reasonable notice, reasonable access during normal business hours to all of the Company’s respective properties, books and records. Each such Significant Holder shall have such other access to management and information as is necessary for it to comply with applicable laws and regulations and reporting obligations.

3.3 Confidentiality. Anything in this Agreement to the contrary notwithstanding, no Holder by reason of this Agreement shall have access to any trade secrets or classified information of the Company. Each Holder acknowledges that the information received by them pursuant to this Agreement may be confidential and for its use only, and it will not use such confidential information in violation of the Exchange Act or reproduce, disclose or disseminate such information to any other person (other than its employees, agents, attorneys, affiliates, limited partners and general partners) and except in connection with the exercise of rights under

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this Agreement, unless the Company has made such information available to the public generally or such Holder is required to disclose such information by a governmental authority.

3.4 D&O Insurance. The Company will, within ninety days of the first issuance of Shares of Series A Preferred Stock pursuant to the Purchase Agreement, obtain director and officer’s insurance in an amount of at least $2 million on terms acceptable to the Investor.

3.5 Option Awards. All option grants or similar awards to persons who are Common Holders (or trustees thereof) (as defined in the Purchase Agreement) will be approved (i) by a Compensation Committee, the majority of the members of which are not executive officers or former executive officers of the Company or (ii) the Preferred Directors, as such term is defined in the Restated Certificate.

3.6 Termination of Covenants. The covenants set forth in this Section 3 shall terminate and be of no further force and effect after the earlier of (i) closing of the Company’s Initial Public Offering and (ii) closing of a Deemed Liquidation.

Section 4

Right of First Refusal

4.1 Right of First Refusal to Significant Holders. The Company hereby grants to each Significant Holder, the right of first refusal to purchase its Pro Rata Share (as defined in the next sentence) of New Securities (as defined in this Section 4.1(a)) which the Company may, from time to time, propose to sell and issue after the date of this Agreement. A Significant Holder’s “Pro Rata Share,” for purposes of this right of first refusal, is equal to the ratio of (a) the number of shares of Common Stock owned by such Significant Holder immediately prior to the issuance of New Securities (assuming full conversion of the Shares and exercise of all outstanding convertible securities, rights, options and warrants, directly or indirectly, into Common Stock held by said Significant Holder) to (b) the total number of shares of Common Stock outstanding immediately prior to the issuance of New Securities (assuming full conversion of the Shares and exercise of all outstanding convertible securities, rights, options and warrants, directly or indirectly, held by all of the Significant Holders).

(a) “New Securities” shall mean any capital stock (including Common Stock) of the Company whether now authorized or not, and Options or Convertible Securities; provided that the term “New Securities” does not include:

(i) securities of the Company issued or issuable to officers, directors and employees of, or consultants to, the Company pursuant to stock grants, option plans, purchase plans or other employee stock incentive programs or arrangements approved by the Board of Directors, or upon exercise of options or warrants granted to such parties pursuant to any such plan or arrangement;

(ii) securities of the Company issued upon the exercise or conversion of Options or Convertible Securities outstanding as of the Original Issue Date (as such term is defined in the Restated Certificate);

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(iii) securities of the Company issued or issuable as a Distribution (as such term is defined in the Restated Certificate) on the Series A Preferred Stock or pursuant to any event for which adjustment is made pursuant to Section 4(e), 4(f) or 4(g) of the Restated Certificate;

(iv) Common Stock issued in an Initial Public Offering;

(v) securities of the Company issued to a bona fide third party pursuant to the acquisition of another corporation by the Company by merger, purchase of substantially all of the assets or other reorganization or to a joint venture agreement, provided, that such issuances are approved by the Board of Directors, and that such issuance is approved by at least one of the Preferred Directors (as such term is defined in the Restated Certificate, the “Preferred Directors”) or that the primary purpose of the issuance is not the raising of capital;

(vi) securities of the Company issued to bona fide third party banks, equipment lessors or other financial institutions pursuant to a debt financing or commercial leasing transaction approved by the Board of Directors, and that such issuance is approved by at least one Preferred Director or that the primary purpose of the issuance is not the raising of capital;

(vii) securities of the Company issued or issuable to bona fide third parties in connection with any settlement of any action, suit, proceeding or litigation approved by the Board of Directors, and that such issuance is approved by at least one Preferred Director or that the primary purpose of the issuance is not the raising of capital;

(viii) securities of the Company issued or issuable to bona fide third parties in connection with sponsored research, collaboration, technology license, development, OEM, marketing or other similar agreements or strategic partnerships approved by the Board of Directors, and that such issuance is approved by at least one Preferred Director or that the primary purpose of the issuance is not the raising of capital;

(ix) securities of the Company issued or issuable to bona fide third party suppliers or bona fide third party service providers in connection with the provision of goods or services pursuant to transactions approved by the Board of Directors, and that such issuance is approved by at least one Preferred Director or that the primary purpose of the issuance is not the raising of capital;

(x) securities of the Company which are otherwise excluded by the affirmative vote or consent of the holders of a majority of the shares of Series A Preferred Stock of the Company then outstanding; and

(xi) any right, option or warrant to acquire any security convertible into the securities excluded from the definition of New Securities pursuant to subsections (i) through (x) above.

(b) In the event the Company proposes to undertake an issuance of New Securities, it shall give each Significant Holder written notice of its intention, describing the type of New Securities, and their price and the general terms upon which the Company proposes to

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issue the same. Each Significant Holder shall have ten (10) days after any such notice is mailed or delivered to agree to purchase such Holder’s pro rata share of such New Securities for the price and upon the terms specified in the notice by giving written notice to the Company, in substantially the form attached hereto as Schedule 1, and stating therein the quantity of New Securities to be purchased.

(c) In the event the Significant Holders fail to exercise fully the right of first refusal rights within said ten (10) day period (the “Election Period”), the Company shall have ninety (90) days thereafter to sell or enter into an agreement (pursuant to which the sale of New Securities covered thereby shall be closed, if at all, within ninety (90) days from the date of said agreement) to sell that portion of the New Securities with respect to which the Significant Holders’ right of first refusal option set forth in this Section 4.1 was not exercised, at a price and upon terms no more favorable to the purchasers thereof than specified in the Company’s notice to Significant Holders delivered pursuant to Section 4.1(b). In the event the Company has not sold within such ninety (90) day period following the Election Period, or such ninety (90) day period following the date of said agreement, the Company shall not thereafter issue or sell any New Securities, without first again offering such securities to the Significant Holders in the manner provided in this Section 4.1.

(d) If at any time (i) the Company creates a direct or indirect subsidiary that is not a wholly owned subsidiary (either directly or indirectly) (other than de minimis ownership to the extent required by applicable laws outside of the United States), (ii) any direct or indirect subsidiary of the Company sells or transfers any shares of capital stock to any entity other than the Company or a direct or indirect wholly owned subsidiary of the Company (other than de minimis ownership to the extent required by applicable laws outside of the United States), (iii) any direct or indirect subsidiary of the Company merges, consolidates or takes any other action that results in such subsidiary not remaining a wholly owned subsidiary of the Company (either directly or indirectly) (other than de minimis ownership to the extent required by applicable laws outside of the United States), or (iv) any direct or indirect subsidiary of the Company sells all or substantially all of its assets to any person or entity other than the Company or a direct or indirect wholly owned subsidiary of the Company, then in each case the Company shall cause such subsidiary (or the surviving or successor entity or purchaser of assets) (each, a “Spin-out Entity”) to provide each Significant Holder a right of first offer (the “Spin-out Preemptive Rights”) to purchase up to its Pro Rata Portion of any Common Stock, Preferred Stock or any other security of the Spin-out Entity, including but not limited to, rights, options, or warrants to purchase such Common Stock, Preferred Stock or other security (“Spin-out Shares”) offered by the Spin-out Entity for financing purposes. The manner and procedure of such Spin-out Preemptive Rights shall be substantially similar to those described in Section 4.1(a)-(c). The Company shall use commercially reasonable efforts to cause, or exert such influence it may have to cause, the organizational documents of the Spin-out Entity (i) to provide for voting rights and preferences equivalent to the voting rights and preferences of the Series A Preferred Stock and (ii) to contain provisions similar to this Section 4.1.

4.2 The rights of the Investor under this Section 4 shall expire upon, and shall not be applicable to the first to occur of (x) immediately before the closing of a Qualified Public Offering (or any other public offering of the Company’s Common Stock registered under the Securities Act consummated in satisfaction of a requested registration pursuant to Section 2.1 (a)

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hereof, an “Investor-Requested Initial Public Offering”) and (y) immediately before closing of a Deemed Liquidation.

Section 5

Miscellaneous

5.1 Amendment. Except as expressly provided herein, neither this Agreement nor any term hereof may be amended, waived, discharged or terminated other than by a written instrument referencing this Agreement and signed by the Company and the holders of a majority of the Registrable Securities. Any such amendment, waiver, discharge or termination effected in accordance with this paragraph shall be binding upon each Holder and each future holder of all such securities of Holder.

5.2 Notices. All notices and other communications required or permitted hereunder shall be in writing and shall be mailed by registered or certified mail, postage prepaid, sent by facsimile or otherwise delivered by hand or by messenger addressed:

(a) if to the Investor, to Oak Investment Partners XI, Limited Partnership, 525 University Avenue, Suite 1300, Palo Alto, California 94301, facsimile number (650)  ###-###-####, attn: Fredric W. Harman and Virginia Eddington, or at such other address and facsimile number as the Investor shall have furnished to the Company, with a copy to Hughes & Luce LLP, 1717 Main Street, Dallas, Texas, 75201, facsimile number (214)  ###-###-####, attn: Benjamin D. Nelson;

(b) if to any Holder, at such Holder’s address and facsimile number as shown in the Company’s records, or, until any such Holder so furnishes an address and facsimile number to the Company, then to and at the address of the last Holder of such shares for which the Company has contact information in its records; or

(c) if to the Company, one copy should be sent to 17150 South Margay Avenue, Carson, CA, 90746, facsimile (310)  ###-###-####, Attn: Chief Executive Officer, or at such other address and facsimile number as the Company shall have furnished to the Investor and Holders, with a copy to Thomas J. Poletti of Kirkpatrick & Lockhart Nicholson Graham LLP located at 10100 Santa Monica Blvd, 7^th Floor, Los Angeles, California, facsimile number (310)  ###-###-####;

Each such notice or other communication shall for all purposes of this Agreement be treated as effective or having been given when delivered if delivered personally, or, if sent by mail, at the earlier of its receipt or 72 hours after the same has been deposited in a regularly maintained receptacle for the deposit of the United States mail, addressed and mailed as aforesaid or, if sent by facsimile, upon confirmation of facsimile transfer when directed to the facsimile number provided as aforesaid.

5.3 Governing Law. This Agreement shall be governed in all respects by the internal laws of the State of California as applied to agreements entered into among California residents to be performed entirely within California, without regard to principles of conflicts of law.

5.4 Successors and Assigns. This Agreement, and any and all rights, duties and obligations hereunder, shall not be assigned, transferred, delegated or sublicensed by the

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Company without the prior written consent of the Investor, and any attempt by the Company without such permission to assign, transfer, delegate or sublicense any rights, duties or obligations that arise under this Agreement shall be void; provided, however, for avoidance of doubt, nothing in this on Section 5.4 shall prohibit the Company from consummating a Deemed Liquidation. Subject to the foregoing and except as otherwise provided herein, the provisions of this Agreement shall inure to the benefit of, and be binding upon, the successors, assigns, heirs, executors and administrators of the parties hereto.

5.5 Entire Agreement. This Agreement and the exhibits hereto constitute the full and entire understanding and agreement between the parties with regard to the subjects hereof. No party hereto shall be liable or bound to any other party in any manner with regard to the subjects hereof or thereof by any warranties, representations or covenants except as specifically set forth herein.

5.6 Delays or Omissions. Except as expressly provided herein, no delay or omission to exercise any right, power or remedy accruing to any party to this Agreement upon any breach or default of any other party under this Agreement shall impair any such right, power or remedy of such non-defaulting party, nor shall it be construed to be a waiver of any such breach or default, or an acquiescence therein, or of or in any similar breach or default thereafter occurring, nor shall any waiver of any single breach or default be deemed a waiver of any other breach or default theretofore or thereafter occurring. Any waiver, permit, consent or approval of any land or character on the part of any party of any breach or default under this Agreement, or any waiver on the part of any party of any provisions or conditions of this Agreement, must be in writing and shall be effective only to the extent specifically set forth in such writing. All remedies, either under this Agreement or by law or otherwise afforded to any party to this Agreement, shall be cumulative and not alternative.

5.7 Severability. If any provision of this Agreement becomes or is declared by a court of competent jurisdiction to be illegal, unenforceable or void, portions of such provision, or such provision in its entirety, to the extent necessary, shall be severed from this Agreement, and such court will replace such illegal, void or unenforceable provision of this Agreement with a valid and enforceable provision that will achieve, to the extent possible, the same economic, business and other purposes of the illegal, void or unenforceable provision. The balance of this Agreement shall be enforceable in accordance with its terms.

5.8 Titles and Subtitles. The titles and subtitles used in this Agreement are used for convenience only and are not to be considered in construing or interpreting this Agreement. All references in this Agreement to sections, paragraphs and exhibits shall, unless otherwise provided, refer to sections and paragraphs hereof and exhibits attached hereto.

5.9 Counterparts. This Agreement may be executed in any number of counterparts, each of which shall be enforceable against the parties that execute such counterparts, and all of which together shall constitute one instrument.

5.10 Telecopy Execution and Delivery. A facsimile, telecopy or other reproduction of this Agreement may be executed by one or more parties hereto and delivered by such party by facsimile or any similar electronic transmission device pursuant to which the signature of or on

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behalf of such party can be seen. Such execution and delivery shall be considered valid, binding and effective for all purposes. At the request of any party hereto, all parties hereto agree to execute and deliver an original of this Agreement as well as any facsimile, telecopy or other reproduction hereof.

5.11 Jurisdiction; Venue. With respect to any disputes arising out of or related to this Agreement, the parties consent to the exclusive jurisdiction of, and venue in, the state courts in Santa Clara County in the State of California (or in the event of exclusive federal jurisdiction, the courts of the Northern District of California).

5.12 Further Assurances. Each party hereto agrees to execute and deliver, by the proper exercise of its corporate, limited liability company, partnership or other powers, all such other and additional instruments and documents and do all such other acts and things as may be necessary to more fully effectuate this Agreement.

5.13 Termination Upon Change of Control. Notwithstanding anything to the contrary herein, this Agreement (excluding any then-existing obligations) shall terminate upon consummation of a Deemed Liquidation.

5.14 Conflict. In the event of any conflict between the terms of this Agreement and the Company’s Restated Certificate or its Bylaws, the terms of the Company’s Restated Certificate or its Bylaws, as the case may be, will control.

5.15 Attorneys’ Fees. In the event that any suit or action is instituted to enforce any provision in this Agreement, the prevailing party in such dispute shall be entitled to recover from the losing party all fees, costs and expenses of enforcing any right of such prevailing party under or with respect to this Agreement, including, without limitation, all fees, costs and expenses of appeals.

[Remainder of Page Intentionally Left Blank]

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IN WITNESS WHEREOF, the parties hereto have executed this Investors’ Rights Agreement effective as of the day and year first above written.

[Signature Page to Investors’ Rights Agreement]

SCHEDULE 1

NOTICE AND WAIVER/ELECTION OF

RIGHT OF FIRST REFUSAL

I do hereby waive or exercise, as indicated below, my rights of first refusal under the Investors Rights Agreement dated as of March 3, 2006 (the “Agreement”):

1. Waiver of ten (10) Days’ Notice Period in Which to Exercise Right of First Offer: (please check only one)

This is neither a commitment to purchase nor a commitment to issue the New Securities described above. Such issuance can only be made by way of definitive documentation related to such issuance. U.S. Auto Parts Network, Inc. will supply you with such definitive documentation upon request or if you indicate that you would like to exercise your first offer rights in whole or in part.