SUPPLEMENTAL INDENTURE 2.300% Senior Notes Due 2016 Dated as of June 23, 2011

Exhibit 4.3

EXECUTION COPY

DANAHER CORPORATION

AND

THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A.,

as Trustee

SUPPLEMENTAL INDENTURE

2.300% Senior Notes Due 2016

Dated as of June 23, 2011

THIS SUPPLEMENTAL INDENTURE (this “ Supplemental Indenture ”), dated as of June 23, 2011, is between DANAHER CORPORATION, a Delaware corporation (the “ Company ”), and THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A., a national banking association, as Trustee (the “ Trustee ”).

RECITALS

WHEREAS, the Company has heretofore executed and delivered to the Trustee an Indenture dated as of December 11, 2007, between the Company and the Trustee (the “ Base Indenture ” and together with this Supplemental Indenture, the “ Indenture ”), providing for the issuance from time to time of series of the Company’s Securities;

WHEREAS, Section 901 (7) of the Base Indenture provides for the Company and the Trustee to enter into an indenture supplemental to the Base Indenture to establish the forms or terms of Securities of any series as permitted by Section 201 or Section 301 of the Base Indenture;

WHEREAS, pursuant to Section 301 of the Base Indenture, the Company wishes to provide for the issuance of a new series of Securities to be known as its 2.300% Senior Notes due 2016 (the “ Notes ”), the form and terms of such Notes and the terms, provisions and conditions thereof to be set forth as provided in this Supplemental Indenture; and

WHEREAS, the Company has requested that the Trustee execute and deliver this Supplemental Indenture and all requirements necessary to make this Supplemental Indenture a valid, binding and enforceable instrument in accordance with its terms, and to make the Notes, when executed by the Company and authenticated and delivered by the Trustee, the valid, binding and enforceable obligations of the Company, have been done and performed, and the execution and delivery of this Supplemental Indenture has been duly authorized in all respects;

NOW, THEREFORE, in consideration of the covenants and agreements set forth herein and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto hereby agree as follows:

ARTICLE 1

DEFINITIONS

Section 1.01 Relation to Base Indenture. This Supplemental Indenture constitutes an integral part of the Base Indenture.

Section 1.02 Definition Of Terms. For all purposes of this Supplemental Indenture:

(a) Capitalized terms used herein without definition shall have the meanings set forth in the Base Indenture;

(b) a term defined anywhere in this Supplemental Indenture has the same meaning throughout;

(c) the singular includes the plural and vice versa;

(d) headings are for convenience of reference only and do not affect interpretation;

(e) the following terms have the meanings given to them in this Section 1.02(e):

“ Business Day ” shall mean any calendar day that is not a Saturday, Sunday or legal holiday in New York, New York and on which commercial banks are open for business in New York, New York.

“ Change of Control ” means the occurrence of any of the following: (1) the consummation of any transaction (including, without limitation, any merger or consolidation) the result of which is that any Person (other than the Company or one of its subsidiaries) becomes the beneficial owner (as defined in Rules 13d-3 and 13d-5 under the Exchange Act), directly or indirectly, of more than 50% of the Company’s Voting Stock or other Voting Stock into which the Company’s Voting Stock is reclassified, consolidated, exchanged or changed, measured by voting power rather than number of shares; (2) the direct or indirect sale, transfer, conveyance or other disposition (other than by way of merger or consolidation), in one or more series of related transactions, of all or substantially all of the Company’s assets and the assets of its subsidiaries, taken as a whole, to one or more Persons (other than the Company or one of its subsidiaries); or (3) the first day on which a majority of the members of our Board of Directors are not Continuing Directors. Notwithstanding the foregoing, a transaction will not be deemed to involve a Change of Control if (1) the Company becomes a direct or indirect wholly-owned subsidiary of a holding company and (2)(A) the direct or indirect holders of the Voting Stock of such holding company immediately following that transaction are substantially the same as the holders of the Company’s Voting Stock immediately prior to that transaction or (B) immediately following that transaction no Person (other than a holding company satisfying the requirements of this sentence) is the beneficial owner, directly of indirectly, of more than 50% of the Voting Stock of such holding company.

“Change of Control Offer” shall have the meaning set forth in Section 3.03.

“ Change of Control Payment ” shall have the meaning set forth in Section 3.03.

“ Change of Control Payment Date ” shall have the meaning set forth in Section 3.03.

“ Change of Control Triggering Event ” shall mean the occurrence of both a Change of Control and a Rating Event.

“ Comparable Treasury Issue ” shall mean the United States Treasury security selected by the Quotation Agent as having an actual or interpolated maturity comparable to the remaining term (“ Remaining Life ”) of the Notes to be redeemed that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the Remaining Life of such Notes.

“ Comparable Treasury Price ” shall mean, with respect to any Redemption Date, (A) the average of four Reference Treasury Dealer Quotations for such Redemption Date, after excluding the highest and lowest such Reference Treasury Dealer Quotations, or (B) if the Company obtains fewer than four such Reference Treasury Dealer Quotations, the average of all such Reference Treasury Dealer Quotations or, (C) if only one such Reference Treasury Dealer Quotation is received, such Reference Treasury Dealer Quotation.

“ Continuing Directors ” means, as of any date of determination, any member of our Board of Directors who (1) was a member of such Board of Directors on the date the Notes were issued or (2) was nominated for election, elected or appointed to such Board of Directors with the approval of a majority of the Continuing Directors who were members of such Board of Directors at the time of such nomination, election or appointment (either by a specific vote or by approval of the Company’s proxy statement in which such member was named as a nominee for election as a director, without objection to such nomination).

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“ Exchange Act ” shall mean the Securities Exchange Act of 1934, as amended.

“ Global Note ” shall have the meaning set forth in Section 2.04.

“ Interest Payment Date ” shall have the meaning set forth in Section 2.05(b).

“ Investment Grade Rating ” means a rating equal to or higher than Baa3 (or the equivalent) by Moody’s and BBB- (or the equivalent) by S&P; and, the equivalent investment grade credit rating from any additional rating agency or rating agencies selected by the Company.

“ Maturity Date ” shall have the meaning set forth in Section 2.02.

“ Moody’s ” shall mean Moody’s Investors Service Inc.

“ Optional Redemption Price ” shall have the meaning set forth in Section 3.01.

“ Person ” has the meaning set forth in the Base Indenture and includes a “person” or “group” as these terms are used in Section 13(d)(3) of the Exchange Act.

“ Quotation Agent ” means the Reference Treasury Dealer appointed by the Company.

“ Rating Agency ” shall mean (1) each of Moody’s and S&P; and (2) if either of Moody’s or S&P ceases to rate the Notes or fails to make a rating of the Notes publicly available for reasons outside of the Company’s control, a “nationally recognized statistical rating organization” within the meaning of Rule 15c3-1(c)(2)(vi)(F) under the Exchange Act selected by the Company (as certified by a resolution of our Board of Directors) as a replacement agency for Moody’s or S&P, or both of them, as the case may be.

“ Rating Event ” means the rating on the Notes is lowered by each of the Rating Agencies and the Notes are rated below an Investment Grade Rating by each of the Rating Agencies on any day within the 60-day period (which 60-day period will be extended so long as the rating of the Notes is under publicly announced consideration for a possible downgrade by any of the Rating Agencies) after the earlier of (1) the occurrence of a Change of Control and (2) public notice of the occurrence of a Change of Control or the Company’s intention to effect a Change of Control; provided, however , that a Rating Event otherwise arising by virtue of a particular reduction in rating will not be deemed to have occurred in respect of a particular Change of Control (and thus will not be deemed a Rating Event for purposes of the definition of Change of Control Triggering Event) if the Rating Agencies making the reduction in rating to which this definition would otherwise apply do not announce or publicly confirm or inform the Trustee in writing at the Company’s or its request that the reduction was the result, in whole or in part, of any event or circumstance comprised of or arising as a result of, or in respect of, the applicable Change of Control (whether or not the applicable Change of Control has occurred at the time of the Rating Event).

“ Record Date ” shall mean, with respect to any Interest Payment Date for the Notes, the fifteenth calendar day, whether or not a Business Day, of the month in which the Interest Payment Date falls.

“ Redemption Date ” shall mean, with respect to any redemption of Notes, the date fixed for such redemption pursuant to the Indenture and such Notes.

“ Reference Treasury Dealer ” means (i) Deutsche Bank Securities Inc., Merrill Lynch, Pierce, Fenner & Smith Incorporated, BNP Paribas Securities Corp., HSBC Securities (USA) Inc. and Wells Fargo Securities, LLC (or their respective affiliates that are Primary Treasury Dealers) and their respective successors; provided , however , that if any of the foregoing shall cease to be a primary U.S.

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Government securities dealer in the United States of America (a “ Primary Treasury Dealer ”), the Company will substitute therefor another Primary Treasury Dealer, and (ii) any other Primary Treasury Dealer selected by the Company.

“ Reference Treasury Dealer Quotations ” means, with respect to each Reference Treasury Dealer and any Redemption Date, the average, as determined by the Company, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Company by the Reference Treasury Dealer at 3:30 p.m., New York City time, on the third Business Day preceding such Redemption Date.

“ S&P ” means Standard & Poor’s Rating Services, a division of The McGraw-Hill Companies, Inc.

“ Treasury Rate ” means, with respect to any Redemption Date, the rate per annum equal to the semiannual equivalent yield to maturity (or interpolated yield to maturity on a day count basis) of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price of such Redemption Date.

“ Voting Stock ” means, with respect to any specified Person as of any date, the capital stock of such Person that is at the time entitled to vote generally in the election of the Board of Directors or similar governing body of such Person.

The terms “ Company ,” “ Trustee ,” “ Indenture ,” “ Base Indenture ,” and “ Notes ” shall have the respective meanings set forth in the recitals to this Supplemental Indenture and the paragraph preceding such recitals.

ARTICLE 2

GENERAL TERMS AND CONDITIONS OF THE NOTES

Section 2.01 Designation and Principal Amount . The Notes may be issued from time to time upon written order of the Company for the authentication and delivery of Notes pursuant to Section 303 of the Base Indenture. There is hereby authorized a series of Securities designated as the 2.300% Senior Notes due 2016, limited in aggregate principal amount to U.S. $500,000,000 (except upon registration of transfer of, or in exchange for, or in lieu of, other Notes pursuant to Sections 304, 305, 306, 906 or 1107 of the Base Indenture).

Section 2.02 Maturity. The date upon which the Notes shall become due and payable at final maturity, together with any accrued and unpaid interest, is June 23, 2016 (the “ Maturity Date ”).

Section 2.03 Form, Payment and Appointment. Except as provided in Section 2.04, the Notes shall be issued in fully registered, certificated form. Principal of and interest on the Notes will be payable, the transfer of such Notes will be registrable, and such Notes will be exchangeable for Notes of a like aggregate principal amount, at the office or agency of the Company maintained for such purpose in Chicago, Illinois, which shall initially be the principal office of the Trustee; provided, however, that payment of interest may be made at the option of the Company by check mailed to the Person entitled thereto at such address as shall appear in the Security register or by wire transfer to an account appropriately designated by the Person entitled to payment; provided, that the Paying Agent shall have received written notice of such account designation at least five Business Days prior to the date of such payment (subject to surrender of the relevant Note in the case of a payment of interest on a Redemption Date or the Maturity Date).

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No service charge shall be made for any registration of transfer or exchange of the Notes, but the Company may require payment from the holder of a sum sufficient to cover any tax or other governmental charge that may be imposed in connection therewith.

The Security Registrar and Paying Agent for the Notes shall initially be the Trustee.

The Notes shall be issuable in denominations of U.S. $2,000 and integral multiples of U.S. $1,000 in excess thereof.

The specified currency of the Notes shall be U.S. Dollars.

Section 2.04 Global Notes. The Notes shall be issued initially in the form of a permanent Global Security in registered form (a “ Global Note ”), deposited with The Depository Trust Company or such other Depositary as any officer of the Company may from time to time designate. Unless and until such Global Note is exchanged for Notes in certificated form, such Global Note may be transferred, in whole but not in part, and any payments on the Notes shall be made only to the Depositary or a nominee of the Depositary, or to a successor Depositary selected or approved by the Company or to a nominee of such successor Depositary.

Section 2.05 Interest. (a)  Interest payable on any Interest Payment Date, the Maturity Date or, if applicable, the Redemption Date, with respect to the Notes shall be the amount of interest accrued from, and including, the immediately preceding Interest Payment Date in respect of which interest has been paid or duly provided for (or from and including the original issue date of June 23, 2011, if no interest has previously been paid or duly provided for with respect to the Notes) to, but excluding, such Interest Payment Date, Maturity Date or, if applicable, Redemption Date, as the case may be (each, an “ Interest Period ”).

(b) The Notes will bear interest at the rate of 2.300% per year from the original issue date thereof through the Maturity Date. Interest on the Notes shall be payable semi-annually in arrears on June 23 and December 23 of each year (each, an “ Interest Payment Date ”), commencing December 23, 2011, to the Persons in whose names the relevant Notes are registered at the close of business on the Record Date for such Interest Payment Date, except as provided in Section 2.05(d).

(c) The amount of interest payable for any full semi-annual Interest Period will be computed on the basis of a 360-day year consisting of twelve 30-day months. The amount of interest payable for any period shorter than a full semi-annual Interest Period for which interest is computed will be computed on the basis of a 30-day month and, for any period less than a month, on the basis of the actual number of days elapsed per 30-day month. In the event that any scheduled Interest Payment Date for the Notes falls on a day that is not a Business Day, then payment of interest payable on such Interest Payment Date will be postponed to the next succeeding day which is a Business Day (and no interest on such payment will accrue for the period from and after such scheduled Interest Payment Date).

(d) In the event that the Maturity Date or a Redemption Date for any Note falls on a day that is not a Business Day, then the related payments of principal, premium, if any, and interest may be made on the next succeeding day that is a Business Day (and no additional interest will accumulate on the amount payable for the period from and after the Maturity Date or Redemption Date, as applicable). Interest due on the Maturity Date or a Redemption Date (in each case, whether or not an Interest Payment Date) of any Notes will be paid to the Person to whom principal of such Notes is payable.

Section 2.06 No Sinking Fund. The Notes are not entitled to the benefit of any sinking fund.

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ARTICLE 3

REDEMPTION OF THE NOTES

Section 3.01 Optional Redemption by Company. Except as otherwise may be specified in this Supplemental Indenture, the Company shall have the right to redeem the Notes, in whole or in part, at any time or from time to time, at its option, at a redemption price (the “ Optional Redemption Price ”) equal to the greater of:

(i) 100% of the principal amount of the Notes to be redeemed; or

(ii) the sum of the present values of the remaining scheduled payments of principal and interest thereon (not including any portion of such payments of interest accrued as of the Redemption Date), discounted to the Redemption Date on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate, plus 15 basis points,

plus in each case accrued interest thereon to, but excluding, the Redemption Date. Notwithstanding the foregoing, installments of interest on Notes that are due and payable on Interest Payment Dates falling on or prior to a Redemption Date will be payable on the Interest Payment Date to the registered holders as of the close of business on the relevant Record Date.

The Company will cause the notice of such redemption to be mailed to the registered holders of the Notes to be redeemed not less than 30 nor more than 60 days prior to the Redemption Date. If the Notes are only partially redeemed pursuant to this Section 3.01, the Notes to be redeemed will be selected by the Trustee in such manner as in its sole discretion it shall deem appropriate and fair; provided , that if at the time of redemption the Notes to be redeemed are registered as a Global Note, the Depositary shall determine, in accordance with its procedures, the principal amount of the Notes to be redeemed held by each of its participants that holds a position in such Notes. The Optional Redemption Price shall be paid prior to 12:00 noon, New York City time, on the Redemption Date or at such later time as is then permitted by the rules of the Depositary for the Notes (if then registered as a Global Note); provided , that the Company shall deposit with the Trustee an amount sufficient to pay the Optional Redemption Price by 10:00 a.m., New York City time, on the date such Optional Redemption Price is to be paid.

If money sufficient to pay the redemption price of all of the Notes (or portions thereof) to be redeemed on the Redemption Date is deposited with the Trustee or Paying Agent on or before the Redemption Date as provided herein, then on and after such Redemption Date, interest will cease to accrue on such Notes (or such portion thereof) called for redemption.

Section 3.02 Special Mandatory Redemption . In the event that the Company does not consummate the Merger (as defined in the Agreement and Plan of Merger, dated as of February 6, 2011 (the “ Merger Agreement ”), among the Company, Djanet Acquisition Corp., a Delaware corporation and an indirect wholly-owned subsidiary of the Company, and Beckman Coulter, Inc.), on or prior to December 31, 2011, or the Merger Agreement is terminated at any time prior thereto, then the Company must redeem all of the Notes on the Special Mandatory Redemption Date (as defined below) at a redemption price (the “ Special Mandatory Redemption Price ”) equal to 101% of the aggregate principal amount of the Notes outstanding, plus accrued and unpaid interest from the most recent Interest Payment Date to which interest has been paid or duly provided for or, if no interest has been paid, from June 23, 2011 to, but excluding, the Special Mandatory Redemption Date.

The “ Special Mandatory Redemption Date ” means the earlier to occur of (1) January 31, 2012, if the Merger has not been completed on or prior to December 31, 2011, or (2) the 30th day (or if such day is not a Business Day, the first Business Day thereafter) following the termination of the Merger Agreement.

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The Company will cause the notice of such Special Mandatory Redemption to be mailed, with a copy to the Trustee, within five Business Days after the occurrence of the event triggering such Special Mandatory Redemption to each holder of Notes at its registered address. The Special Mandatory Redemption Price shall be paid prior to 12:00 noon, New York City time, on the Special Mandatory Redemption Date or at such later time as is then permitted by the rules of the Depositary for the Notes (if then registered as a Global Note); provided , that the Company shall deposit with the Trustee an amount sufficient to pay the Special Mandatory Redemption Price by 10:00 a.m., New York City time, on the date such Special Mandatory Redemption Price is to be paid.

If money sufficient to pay the Special Mandatory Redemption Price of all of the Notes to be redeemed on the Special Mandatory Redemption Date is deposited with the Trustee or Paying Agent on or before the Special Mandatory Redemption Date as provided herein, then on and after such Special Mandatory Redemption Date, interest will cease to accrue on such Notes (or such portion thereof) called for redemption.

Section 3.03 Change of Control Triggering Event. If a Change of Control Triggering Event occurs, unless the Company has exercised its right to redeem the Notes as described in Section 3.01 or Section 3.02, holders of Notes will have the right to require the Company to repurchase all or any part (equal to $2,000 or an integral multiple of $1,000 in excess thereof) of their Notes pursuant to the offer described below (the “ Change of Control Offer ”) on the terms set forth in the Notes. In the Change of Cont