Document:

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                                                                    Exhibit 4.15

                 CONSENT, AMENDMENT, ASSIGNMENT AND ASSUMPTION

                                    OF THE

         DRESSER, INC. AMENDED AND RESTATED INVESTOR RIGHTS AGREEMENT

   This Consent, Amendment, Assignment and Assumption of the Dresser, Inc.
Amended and Restated Investor Rights Agreement (this "Consent") is made and
entered into as of July __, 2002, by DEG Acquisitions, LLC (the "LLC"),
Dresser, Inc., a Delaware corporation ("Dresser") and Dresser, Ltd., a Bermuda
company ("Dresser Bermuda").

                                R E C I T A L S

   WHEREAS, the LLC owns 9,700,000 shares of Class A Common Stock, par value
$.001 per share (the "Class A Common Stock") and 550,000 shares of Class B
Common Stock, par value $.001 per share (the "Class B Common Stock" and,
together with the Class A Common Stock, the "Dresser Common Stock") of Dresser;

   WHEREAS, Dresser heretofore entered into an Agreement and Plan of Merger
(the "Merger Agreement") among Dresser Mergeco, Inc., a Delaware corporation,
Dresser Bermuda and Dresser.

   WHEREAS, as a result of the transactions contemplated by the Merger
Agreement (the "Merger"), each outstanding share of Dresser Common Stock will
be cancelled and the holders thereof will receive one class A common share of
Dresser Bermuda, par value $.01 (the "Bermuda Class A Common Shares"), for each
share of Class A Common Stock and one class B common share of Dresser Bermuda,
par value $.01 (the "Bermuda Class B Common Shares" and, collectively with the
Bermuda Class A Common Shares, the "Bermuda Common Shares"), for each share of
Class B Common Stock, respectively, held by such stockholder;

   WHEREAS, Dresser and the LLC are parties to that certain Amended and
Restated Investor Rights Agreement, dated as of June 12, 2001, as amended from
time to time (the "IRA"), among the LLC, Dresser, Dresser Industries, Inc., a
Delaware corporation, and each of the stockholders and individual employees of
Dresser who become party thereto from time to time in accordance with the terms
thereof (collectively with the LLC, the "Stockholders");

   WHEREAS, Dresser wishes to assign its rights and obligations under the IRA
to Dresser Bermuda, and Dresser Bermuda wishes to assume such rights and
obligations, effective upon completion of the Merger, so that the relative
rights and obligations of the parties to the IRA as they related to the
Stockholders' ownership of shares of Dresser Common Stock prior to the Merger
will be the relative rights and obligations of the parties to the IRA as they
relate to the Stockholders' ownership of Bermuda Common Shares following the
Merger;

   WHEREAS, Dresser and Dresser Bermuda wish to amend the IRA to provide that
references to Dresser and the "Company" will be changed to refer to Dresser
Bermuda for all purposes under the IRA;

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   WHEREAS, Section 5.2 of the IRA provides that any provision of the IRA, may
be amended or waived with the written consent of at least sixty-six and
two-thirds percent (66 2/3%) of the outstanding shares of Dresser Common Stock
that are subject to the IRA and owned by the parties thereto, with certain
exceptions not relevant here;

   WHEREAS, this Consent will not disproportionately and adversely affect any
Employee Stockholder (as defined in the IRA) or the Employee Stockholders as a
group; and

   WHEREAS, the LLC holds more than 66 2/3% of the outstanding shares of
Dresser Common Stock that are subject to the IRA, and pursuant to Section 5.2
of the IRA, the LLC wishes to consent to the assignment, assumption and
amendment referred to above.

   NOW, THEREFORE:

   1.  Dresser hereby grants, transfers and assigns to Dresser Bermuda all of
Dresser's right, title and interest in the IRA and all of its obligations
thereunder.

   2.  Dresser Bermuda hereby does absolutely and irrevocably assume and agrees
to perform and discharge all of Dresser's obligations under the IRA.

   3.  The IRA is hereby amended as follows:

   a)  All references to "Dresser, Inc." shall be changed to "Dresser, Ltd."
       and the defined term the "Company" shall mean Dresser, Ltd.

   b)  All references to "Class A Common Stock, par value $.001 per share",
       shares of "Class A Common Stock" and similar phrases shall refer to the
       Class A common shares, par value U.S. $.01 per share, of the Company,
       and all references to "Class B Common Stock, par value $.001 per share",
       shares of "Class B Common Stock" and similar phrases shall refer to the
       Class B common shares, par value U.S. $.01 per share, of the Company.

   c)  All references to the "Corporation" in Section 6 shall be changed to the
       "Company".

   d)  All references to "Certificate of Incorporation" and "Bylaws" shall be
       changed to "Memorandum of Association" and "Bye-Laws", respectively.

   4.  The IRA is hereby amended to the extent necessary to permit completion
of the Merger and the receipt by the parties to the IRA of the Bermuda Common
Shares in connection therewith. To the extent applicable, the LLC hereby waives
the requirements of Section 3.5(a)(ii), the notice and delivery requirements in
Section 3.5(b) and (c) and the expense reimbursement requirements of Section
3.5(d).

   5.  The LLC hereby consents to the above mentioned assignment, assumption
and amendment.

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   6.  This Consent is intended solely for the purpose described in Sections 1,
2, 3, 4 and 5 above, and is not a general waiver of the IRA. Except as
specifically set forth herein, the IRA shall remain in full force and effect.

   7.  This Consent shall be governed by and construed exclusively in
accordance with the internal laws of the State of Delaware, excluding that body
of law relating to conflict of laws and choice of law.

                           [SIGNATURE PAGE FOLLOWS]

                                      3

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   IN WITNESS WHEREOF, the undersigned have executed this Consent as of the
date first written above.

            DEG ACQUISITIONS, LLC

                FIRST RESERVE FUND VIII, L.P.,
                  a Delaware limited partnership

                       By: FIRST RESERVE GP VIII, L.P.
                             a Delaware limited partnership, its general partner

                           By: FIRST RESERVE CORPORATION,
                                 a Delaware corporation, its general partner

                                                 By: ________________________
                                                     Name:
                                                     Title:
            Dresser, Inc.

            By: ________________________
                Name:
                Title:

            Dresser, Ltd.

            By: ________________________
                Name:
                Title:<PAGE>

                                                                    Exhibit 4.16

                 CONSENT, AMENDMENT, ASSIGNMENT AND ASSUMPTION

                                      OF

                    DRESSER, INC. SPONSOR RIGHTS AGREEMENT

     This Consent, Amendment, Assignment and Assumption of the Dresser, Inc.
Sponsor Rights Agreement (this "Consent") is made and entered into as of July 3,
2002, by DEG Acquisitions, LLC, a Delaware limited liability company ("DEG"),
First Reserve Fund VIII, L.P. ("Fund VIII"), First Reserve Fund IX, L.P. ("Fund
IX"), Odyssey Investment Partners Fund, LP ("Odyssey Fund"), Odyssey
Coinvestors, LLC ("Coinvestors"), DI Coinvestment, LLC ("DI" and, together with
Odyssey Fund and Coinvestors, "Odyssey") Dresser, Inc., a Delaware corporation
("Dresser"), and Dresser, Ltd., a Bermuda company ("Dresser Bermuda").

                                 R E C I T A L S

     WHEREAS, DEG owns 9,700,000 shares of Class A Common Stock, par value $.001
per share (the "Class A Common Stock") and 550,000 shares of Class B Common
Stock, par value $.001 per share (the "Class B Common Stock" and, together with
the Class A Common Stock, the "Dresser Common Stock") of Dresser;

     WHEREAS, Dresser heretofore entered into an Agreement and Plan of Merger
(the "Merger Agreement") among Dresser Mergerco, Inc., a Delaware corporation,
Dresser Bermuda and Dresser.

     WHEREAS, as a result of the transactions contemplated by the Merger
Agreement (the "Merger"), each outstanding share of Dresser Common Stock will be
cancelled and the holders thereof will receive one class A common share of
Dresser Bermuda, par value $.01 (the "Bermuda Class A Common Shares"), for each
share of Class A Common Stock and one class B common share of Dresser Bermuda,
par value $.01 (the "Bermuda Class B Common Shares" and, collectively with the
Bermuda Class A Common Shares, the "Bermuda Common Shares"), for each share of
Class B Common Stock, respectively, held by such stockholder;

     WHEREAS, DEG, Dresser, Fund VIII, Fund IX and Odyssey are all of the
parties to that certain Sponsor Rights Agreement, dated as of April 10, 2001, as
amended from time to time (the "SRA"), pursuant to which Fund VIII, Fund IX and
Odyssey (collectively, the "Sponsors") have certain rights with respect to their
indirect ownership of the Dresser Common Stock;

     WHEREAS, without affecting the rights and obligations of the parties to the
SRA (except as expressly set forth in this Consent), Dresser wishes to assign
its rights and obligations under the SRA to Dresser Bermuda and Dresser Bermuda
wishes to assume such rights and obligations, effective upon completion of the
Merger, so that the relative rights and obligations of the parties to the SRA as
they related to the Sponsors' ownership of shares of Dresser Common Stock prior
to the Merger will be the relative rights and obligations of the Parties to the
SRA as they relate to the Sponsors' ownership of Bermuda Common Shares following
the Merger;

<PAGE>

     WHEREAS, Dresser and Dresser Bermuda wish to amend the SRA to provide that
references to Dresser and the "Company" will be changed to refer to Dresser
Bermuda for all purposes under the SRA;

     WHEREAS, pursuant to Section 6.2 of the SRA, the compliance with any
provision of the SRA can be amended or waived with the written consent of all
"Stockholders" (as defined in the SRA) party to the SRA that hold, directly or
indirectly, more than 1% of the shares subject to the SRA;

     WHEREAS, DEG, Fund VIII, Fund IX and Odyssey are the sole "Stockholders"
party to the SRA that hold, directly or indirectly, more than 1% of the shares
subject to the SRA and Fund VIII, Fund IX and Odyssey are all of the members of
DEG; and

     WHEREAS, DEG, Fund VIII, Fund IX, Dresser and Dresser Bermuda wish to
consent to the assignment, assumption and amendment referred to above to give
effect to such actions without otherwise affecting the rights and obligations of
the parties to the SRA;

     NOW, THEREFORE:

     1. Dresser hereby grants, transfers and assigns to Dresser Bermuda all of
Dresser's right, title and interest in the SRA and all of its obligations
thereunder.

     2. Dresser Bermuda hereby does absolutely and irrevocably assume and agrees
to perform and discharge all of Dresser's obligations under the SRA.

     3. The SRA is hereby amended as follows:

     a)   All references to "Dresser, Inc." shall be changed to "Dresser, Ltd."
          and the defined term the "Company" shall mean Dresser, Ltd.

     b)   All references to "Class A Common Stock, par value $.001 per share",
          shares of "Class A Common Stock" and similar phrase shall refer to the
          Class A common shares, par value U.S. $.01 per share, of the Company,
          and all references to "Class B Common Stock, par value $.001 per
          share", shares of "Class B Common Stock" and similar phrases shall
          refer to the Class B common shares, par value U.S. $.01 per share, of
          the Company.

     c)   All references to the "Corporation" in Section 7 shall be changed to
          the "Company".

     d)   All references to "Certificate of Incorporation" and "Bylaws" shall be
          changed to "Memorandum of Association" and "Bye-Laws".

     4. DEG, Fund VIII, Fund IX and Odyssey, pursuant to Section 6.2 of the SRA,
hereby agree to amend Section 2.5 of the SRA by deleting the first sentence of
the first paragraph thereof in its entirety and replacing it with the following:

                                      2

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          "Management of the Company. The Company will not take any of the
     following actions and will not permit any of its subsidiaries to take any
     of the following actions (each a "Restricted Action"), unless, in addition
     to any other consents or approvals that may be required to effect such
     Restricted Action, such Restricted Action is approved by a majority of the
     Board that includes at least one (1) Board Designee designated by FRC and
     one (1) Board Designee designated by OIPF.

     5. DEG, Fund VIII, Fund IX and Odyssey, pursuant to Section 6.2 of the SRA,
hereby agree to amend Section 2.5 of the SRA by adding the following paragraphs
immediately prior to the final paragraph thereof:

          "If an affiliate of either Sponsor who is not an employee of the
     Company or any of its subsidiaries is appointed to a committee or
     sub-committee of the Board or the board of directors of any subsidiary of
     the Company or any committee or sub-committee thereof, then the Company
     will also appoint or cause to be appointed at least one designee of the
     other Sponsor to such committee or sub-committee of the Board, subsidiary
     board of directors, or committee or sub-committee thereof; provided that if
     any Sponsor at any time owns less than 5% of the combined voting power of
     the Company, then such Sponsor shall no longer be entitled to designate any
     member of a committee or sub-committee of the Board or the board of
     directors of any subsidiary of the Company or any committee or
     sub-committee thereof. Any determination of voting power pursuant to this
     Section shall be made in the same manner as the calculation in 2.3(a)
     above.

          From and after the date of this Consent, without the written consent
     of each of the Sponsors, the Company will not, and will cause its
     subsidiaries not to, take any action (including, without limitation, any
     distribution of assets by Dresser Inc. to its stockholders) that would
     result in inclusion by any Sponsor, or any direct or indirect owner of any
     Sponsor, of Subpart F income (as defined in Section 952 of the United
     States Internal Revenue Code of 1986, as amended (the "Code")), income
     pursuant to Section 951(a)(1)(B) of the Code or undistributed foreign
     personal holding company income pursuant to Section 551(b) of the Code."

     6. DEG, Fund VIII, Fund IX and Odyssey, pursuant to Section 6.2 of the SRA,
hereby agree to amend Section 7 of the SRA by deleting the first two sentences
of the first paragraph thereof in its entirety and replacing it with the
following:

          "Each certificate representing shares of capital stock of the Company
     now or hereafter owned by a Stockholder party to this agreement shall be
     endorsed with the following legend:"

     7. DEG, Fund VIII, Fund IX and Odyssey each hereby consent to the above
mentioned assignment, assumption and amendment.

                                      3

<PAGE>

     8. This Consent is intended solely for the purpose described in Sections 1,
2, 3, 4, 5 and 6 above, and is not a general waiver of the SRA. Except as
specifically set forth herein, the SRA shall remain in full force and effect.

     9. The Company shall pay reasonable out-of-pocket costs and expenses
(including attorneys' and accountants' fees) of the Sponsors incurred in
connection with the preparation and execution of this Consent, the transactions
described in the Recitals hereto and any necessary or advisable internal
restructuring of the Sponsors' investment vehicles arising out of the foregoing.
The Sponsors shall endeavor to minimize such expenses by coordinating their use
of counsel and advisors to complete the foregoing.

     10. This Consent shall be governed by and construed exclusively in
accordance with the internal laws of the State of Delaware, excluding that body
of law relating to conflict of laws and choice of law.

                            [SIGNATURE PAGE FOLLOWS]

                                        4

<PAGE>

     IN WITNESS WHEREOF, the undersigned have executed this Consent as of the
date first written above.

          DEG ACQUISITIONS, LLC

              FIRST RESERVE FUND VIII, L.P.,
               a Delaware limited partnership, its manager

                   By: FIRST RESERVE GP VIII, L.P.
                        a Delaware limited partnership, its general partner

                       By: FIRST RESERVE CORPORATION,
                            a Delaware corporation, its general partner

                                   By: _______________________
                                       Name:
                                       Title:

          FIRST RESERVE FUND VIII, L.P.,
           a Delaware limited partnership

              By: FIRST RESERVE GP VIII, L.P.
                   a Delaware limited partnership, its general partner

                   By: FIRST RESERVE CORPORATION,
                        a Delaware corporation, its general partner

                            By: ______________________________
                                Name:
                                Title:

          FIRST RESERVE FUND IX, L.P.,
           a Delaware limited partnership

              By: FIRST RESERVE GP IX, L.P.
                   a Delaware limited partnership, its general partner

                   By: FIRST RESERVE GP IX, INC.,
                        a Delaware corporation, its general partner

                            By: ____________________________
                                Name:
                                Title:

<PAGE>

          ODYSSEY INVESTMENT PARTNERS FUND, LP,
           a Delaware limited partnership

                 By: ODYSSEY CAPITAL PARTNERS, LLC,
                      a Delaware limited liability company, its general partner

                                   By: _______________________
                                       Name:
                                       Title:

          ODYSSEY COINVESTORS, LLC,
           a Delaware limited liability company

                 By: ODYSSEY INVESTMENT PARTNERS, LLC,
                      a Delaware limited liability company, its manager

                                   By: _______________________
                                       Name:
                                       Title:

          DI COINVESTMENT, LLC,
           a Delaware limited liability company

                 By: ODYSSEY INVESTMENT PARTNERS, LLC,
                      a Delaware limited liability company, its manager

                                   By: _______________________
                                       Name:
                                       Title:

<PAGE>

                       DRESSER, INC.

                                   By: _______________________
                                       Name:
                                       Title:

                       DRESSER, LTD.

                                   By: _______________________
                                       Name:
                                       Title:

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