Confirmation of Forward Stock Sale Transaction

Exhibit 4.1

EXECUTION VERSION

May 19, 2009

Confirmation of Forward Stock Sale Transaction

Dear Sir/Madam:

The purpose of this letter agreement (this “Confirmation”) is to confirm the terms and conditions of the Transaction entered into between Morgan Stanley & Co. International plc (“Party A”) and Beckman Coulter, Inc. (“Party B”) on the Trade Date specified below (the “Transaction”). This confirmation constitutes a “Confirmation” as referred to in the ISDA Master Agreement specified below.

The definitions and provisions contained in the 2002 ISDA Equity Derivatives Definitions (as published by the International Swaps and Derivatives Association, Inc. (“ISDA”)) (the “Equity Definitions”) are incorporated into this Confirmation. In the event of any inconsistency between the Equity Definitions and this Confirmation, this Confirmation will govern. Any reference to a currency shall have the meaning contained in Annex A to the 1998 ISDA FX and Currency Option Definitions, as published by ISDA.

GENERAL TERMS:

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SETTLEMENT TERMS:

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Conditions to Effectiveness:

The effectiveness of this Confirmation on the Effective Date shall be subject to (i) the condition that the representations and warranties of Party B contained in the Underwriting Agreement and any certificate delivered pursuant thereto by Party B be true and correct on the Effective Date as if made as of the Effective Date, (ii) the condition that Party B have performed all of the obligations required to be performed by it under the Underwriting Agreement on or prior to the Effective Date, and (iii) the satisfaction of all of the conditions set forth in Section 6 of the Underwriting Agreement. In addition, if Party A, in its sole judgment, is unable to borrow and deliver for sale a number of Shares equal to the Base Shares or if, in Party A’s sole judgment it would entail a stock loan cost of more than 200 basis points per annum with respect to all or any portion of such Shares, the effectiveness of this Confirmation shall be limited to the number of Shares Party A may borrow at a cost of not more than 200 basis points per annum.

Additional Representations, Warranties and Agreements of Party B: Party B hereby represents and warrants to, and agrees with, Party A as of the date hereof and on the Effective Date that:

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Tax Representations:

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If such representation applies, then:

“Specified Treaty” means, with respect to a Transaction, the tax treaty applicable between the United States of America and the United Kingdom.

“Specified Jurisdiction” means the United States of America.

Party A is a ‘non-U.S. branch of a foreign person’ as that term is used in section 1.1441-4(a)(3)(ii) of the U.S. Treasury Regulations (the “Regulations”), and Party A is a ‘foreign person’ as that term is used in section 1.6041-4(a)(4) of the Regulations.

Agreement to Deliver Documents:

For the purpose of Section 4(a)(i) and (ii) of the Agreement, each party agrees to deliver the following documents as applicable:

Tax forms, document or certificates to be delivered are:

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Covenant of Party B:

The parties acknowledge and agree that any Shares delivered by Party B to Party A on any Settlement Date will be newly issued Shares and when delivered by Party A (or an affiliate of Party A) to securities lenders from whom Party A (or an affiliate of Party A) borrowed Shares in connection with hedging its exposure to the Transaction will be freely saleable without further registration or other restrictions under the Securities Act in the hands of those securities lenders, irrespective of whether such stock loan is effected by Party A or an affiliate of Party A to hedge Party A’s exposure under the Transaction. Accordingly, Party B agrees that the Settlement Shares that it delivers to Party A on each Settlement Date will not bear a restrictive legend and that such Settlement Shares will be deposited in, and the delivery thereof shall be effected through the facilities of, the Clearance System.

Covenants of Party A:

Acceleration Events: An Acceleration Event shall occur if:

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Termination Settlement:

If a Settlement Date is specified following an Acceleration Event (a “Termination Settlement Date”), Physical Settlement shall apply with respect to such Termination Settlement Date as set forth above, and subject to the provisions described under “Limit on Beneficial Ownership” below. If, upon designation of a Termination Settlement Date by Party A, Party B fails to deliver the Settlement Shares relating to such Termination Settlement Date when due or otherwise fails to perform its obligations in connection therewith, it shall be an Event of Default with respect to Party B and Section 6 of the Agreement shall apply. If an Acceleration Event occurs during an Unwind Period relating to a number of Settlement Shares to which Cash Settlement or Net Share Settlement applies, then on the Termination Settlement Date relating to such Acceleration Event, notwithstanding any election to the contrary by Party B, Cash Settlement or Net Share Settlement (as previously elected by Party B) shall apply to the portion of the Settlement Shares relating to such Unwind Period as to which Party A has unwound its hedge, and Physical Settlement shall apply in respect of (x) the remainder (if any) of such Settlement Shares and (y) the Settlement Shares designated by Party A in respect of such Termination Settlement Date.

Private Placement Procedures:

If Party B is unable to comply with the provisions of “Covenant of Party B” above because of a change in law or a change in the policy of the Securities and Exchange Commission or its staff, or Party A

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otherwise determines that in its reasonable opinion, based on the advice of counsel, any Settlement Shares to be delivered to Party A by Party B may not be freely returned by Party A or its affiliates to securities lenders as described under “Covenant of Party B” above, then delivery of any such Settlement Shares (the “Restricted Shares”) shall be effected pursuant to Annex A hereto, unless waived by Party A.

Rule 10b5-1:

It is the intent of Party A and Party B that the purchase of Shares by Party A during any Unwind Period comply with the requirements of Rule 10b5-1(c)(i)(B) of the Exchange Act and that this Confirmation shall be interpreted to comply with the requirements of Rule 10b5-1(c).

Party B acknowledges that, except as otherwise provided herein, (i) during any Unwind Period Party B does not have, and shall not attempt to exercise, any influence over how, when or whether to effect purchases of Shares by Party A (or its agent or affiliate) in connection with this Confirmation and (ii) Party B is entering into the Agreement and this Confirmation in good faith and not as part of a plan or scheme to evade compliance with federal securities laws including, without limitation, Rule 10b-5 promulgated under the Exchange Act.

Party B hereby agrees with Party A that during any Unwind Period Party B shall not communicate, directly or indirectly, any material non-public information (within the meaning of any applicable securities laws) to any Equity Personnel (as defined below). “Equity Personnel” means any employee on the trading side of Morgan Stanley & Co. Incorporated and does not include Anthony Cicia.

Interpretive Letter:

The parties intend for this Confirmation to constitute a “Contract” as described in the letter dated October 6, 2003 submitted by Robert W. Reeder and Leslie N. Silverman to Paula Dubberly of the staff of the Securities and Exchange Commission (the “Staff”) to which the Staff responded in an interpretive letter dated October 9, 2003.

Maximum Share Delivery:

Notwithstanding any other provision of this Confirmation, in no event will Party B be required to deliver on any Settlement Date, whether pursuant to Physical Settlement, Net Share Settlement, Termination Settlement or Private Placement Settlement, more than 4,500,000 Shares to Party A.

Assignment:

Party A may assign or transfer any of its rights or delegate any of its duties hereunder to any affiliate of Party A or any entity organized or sponsored by Party A without the prior written consent of Party B; provided that such assignee’s obligations shall be guaranteed by Morgan Stanley. Notwithstanding any other provision of this Confirmation to the contrary requiring or allowing Party A to purchase or receive any Shares from Party B, Party A may designate any of its affiliates to purchase or receive such Shares or otherwise to perform Party A’s obligations in respect of the Transaction and any such designee may assume such obligations, and Party A shall be discharged of its obligations to Party B to the extent of any such performance.

Guarantee of Party A

Morgan Stanley shall guarantee all obligations of Party A under this Confirmation and shall execute a Guarantee in the form attached as Annex B in favor of Party B. The Guarantee shall be a Credit Support Document.

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Matters Relating to Agent:

Indemnity:

Party B agrees to indemnify Party A and its affiliates and their respective directors, officers, agents and controlling parties (Party A and each such affiliate or person being an “Indemnified Party”) from and against any and all losses, claims, damages and liabilities, joint and several, incurred by or asserted against such Indemnified Party arising out of, in connection with, or relating to, any breach of any covenant or representation made by Party B in this Confirmation or the Agreement and will reimburse any Indemnified Party for all reasonable expenses (including reasonable legal fees and expenses) as they are incurred in connection with the investigation of, preparation for, or defense of any pending or threatened claim or any action or proceeding arising therefrom, whether or not such Indemnified Party is a party thereto. Party B will not be liable under this Indemnity paragraph to the extent that any loss, claim, damage, liability or expense is found in a final and nonappealable judgment by a court of competent jurisdiction to have resulted from Party A’s gross negligence, fraud, bad faith and/or willful misconduct.

Miscellaneous:

Status of Claims in Bankruptcy:

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Party A acknowledges and agrees that this confirmation is not intended to convey to Party A rights with respect to the transactions contemplated hereby that are senior to the claims of common stockholders in any U.S. bankruptcy proceedings of Party B; provided, however, that nothing herein shall limit or shall be deemed to limit Party A’s right to pursue remedies in the event of a breach by Party B of its obligations and agreements with respect to this Confirmation and the Agreement; and provided further, that nothing herein shall limit or shall be deemed to limit Party A’s rights in respect of any transaction other than the Transaction.

Agreement Regarding Set-off and Collateral:

Notwithstanding Section 6(f) or any other provision of the Agreement or any other agreement between the parties to the contrary, the obligations of Party B hereunder are not secured by any collateral. Obligations under the Transaction shall not be set off against any other obligations of the parties, whether arising under the Agreement, this Confirmation, under any other agreement between the parties hereto, by operation of law or otherwise, and no other obligations of the parties shall be set off against obligations under the Transaction, whether arising under the Agreement, this Confirmation, under any other agreement between the parties hereto, by operation of law or otherwise, and each party hereby waives any such right of setoff. In calculating any amounts under Section 6(e) of the Agreement, notwithstanding anything to the contrary in the Agreement, (a) separate amounts shall be calculated as set forth in such Section 6(e) with respect to (i) the Transaction and (ii) all other Transactions, and (b) such separate amounts shall be payable pursuant to Section 6(d)(ii) of the Agreement.

Bankruptcy:

Notwithstanding anything to the contrary herein, in the Agreement or in the Equity Definitions, upon the occurrence of an Insolvency, Insolvency Filing of Party B or an Event of Default of the type described in Section 5(a)(vii) of the Agreement (a “Bankruptcy”) with respect to Party B, the Transaction shall automatically terminate on the date of such occurrence without further liability of either party under this Confirmation to the other party (except for any liability in respect of any breach of representation or covenant by a party under this Confirmation prior to the date of such Insolvency, Insolvency Filing or Bankruptcy).

Limit on Beneficial Ownership:

Notwithstanding any other provisions hereof, Party A shall not be entitled to take delivery of any Shares deliverable hereunder (whether in connection with the purchase of Shares on any Settlement Date or any Termination Settlement Date, any Private Placement Settlement or otherwise) to the extent (but only to the extent) that, after such receipt of any Shares hereunder, Party A and each person subject to aggregation of Shares with Party A under Section 13 or Section 16 of the Exchange Act and rules promulgated thereunder (the “Party A Group”) would directly or indirectly beneficially own (as such term is defined for purposes of Section 13 or Section 16 of the Exchange Act and rules promulgated thereunder) in excess of 9.0% of the then outstanding Shares (the “Threshold Number of Shares”). Any purported delivery hereunder shall be void and have no effect to the extent (but only to the extent) that, after such delivery, the Party A Group would directly or indirectly so beneficially own in excess of the Threshold Number of Shares. If any delivery owed to Party A hereunder is not made, in whole or in part, as a result of this provision, Party B’s obligation to make such delivery shall not be extinguished and Party B shall make such delivery as promptly as practicable after, but in no event later than one Clearance System Business Day after, Party A gives notice to Party B that, after such delivery, the Party A Group would not directly or indirectly so beneficially own in excess of the Threshold Number of Shares.

In addition, notwithstanding anything herein to the contrary, if any delivery owed to Party A hereunder is not made, in whole or in part, as a result of the immediately preceding paragraph, Party A shall be permitted to make any payment due in respect of such Shares to Party B in two or more tranches that

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correspond in amount to the number of Shares delivered by Party B to Party A pursuant to the immediately preceding paragraph.

If Net Share Settlement would result in the Party A Group directly or indirectly beneficially owning (as such term is defined for purposes of Section 13 or Section 16 of the Exchange Act and rules promulgated thereunder) in excess of 9.0% of the then outstanding Shares in connection with closing out its hedge position, Party A would be allowed to partially settle the Transaction based on its purchase of that amount of Shares, and then to purchase the amount or amounts of additional Shares necessary to settle the remainder of the Transaction, and to make the associated deliveries at such times as determined by the Calculation Agent.

Other Forward:

Party A acknowledges that Party B has entered into two substantially identical forward transactions for its Shares on the date hereof (the “Other Forwards”) with an affiliate of Goldman, Sachs & Co. Party A and Party B agree that if Party B designates a Settlement Date with respect to either of the Other Forwards and for which Cash Settlement or Net Share Settlement is applicable, and the resulting Unwind Period for such Other Forward coincides for any period of time with an Unwind Period for the Transaction (the “Overlap Unwind Period”), Party B shall notify Party A prior to the commencement of such Overlap Unwind Period, and Party A shall only be permitted to purchase Shares to unwind its hedge in respect of the Transaction on every other Exchange Business Day that is not a Suspension Day during such Overlap Unwind Period, commencing on the first day of such Overlap Unwind Period; provided that if such first day of such Overlap Unwind Period is a day on which Party A is contractually prohibited from purchasing Shares to unwind its hedge in respect of any other transaction pursuant to any provision substantially similar to the provision immediately preceding this proviso, then Party A shall only be permitted to purchase Shares to unwind its hedge in respect of the Transaction on every other Exchange Business Day during such Overlap Unwind Period, commencing on the second day of such Overlap Unwind Period.

Severability:

If any term, provision, covenant or condition of this Confirmation, or the application thereof to any party or circumstance, shall be held to be invalid or unenforceable in whole or in part for any reason, the remaining terms, provisions, covenants, and conditions hereof shall continue in full force and effect as if this Confirmation had been executed with the invalid or unenforceable provision eliminated, so long as this Confirmation as so modified continues to express, without material change, the original intentions of the parties as to the subject matter of this Confirmation and the deletion of such portion of this Confirmation will not substantially impair the respective benefits or expectations of parties to this Agreement; provided, however, that this severability provision shall not be applicable if any provision of Section 2, 5, 6 or 13 of the Agreement (or any definition or provision in Section 14 to the extent that it relates to, or is used in or in connection with any such Section) shall be so held to be invalid or unenforceable.

Miscellaneous:

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Please confirm that the foregoing correctly sets forth the terms of our agreement by signing and returning this Confirmation.

Confirmed as of the date first written above:

SCHEDULE I

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ANNEX A

PRIVATE PLACEMENT PROCEDURES

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ANNEX B

FORM OF MS GUARANTEE

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