Exhibit 10.10

MERGER OF THE
PETRECO INTERNATIONAL, INC.
401(k) PROFIT SHARING PLAN
WITH AND INTO THE
COOPER CAMERON CORPORATION
RETIREMENT SAVINGS PLAN

     WHEREAS, Cooper Cameron Corporation (the “Company”) sponsors the Cooper
Cameron Corporation Retirement Savings Plan (the “Cooper Cameron Plan”) and the
Petreco International, Inc. 401(k) Profit Sharing Plan (the “Petreco Plan”); and

     WHEREAS, the Company desires that the Petreco Plan be merged with and into
the Cooper Cameron Plan, effective as of January 1, 2005;

     NOW, THEREFORE, effective as of January 1, 2005 (the “Plan Merger Date”),
in consideration of the foregoing and notwithstanding any provisions of the
Petreco Plan and the Cooper Cameron Plan to the contrary, the Petreco Plan shall
be merged with and into the Cooper Cameron Plan as follows:

     1. The Petreco Plan is hereby amended, restated, and merged with and into
the Cooper Cameron Plan, with the result that the provisions of the Cooper
Cameron Plan, as modified herein, replace in their entirety the provisions of
the Petreco Plan. Any provisions of the Cooper Cameron Plan required to have an
earlier effective date by applicable statute and/or regulation shall be
effective as of the required effective date in such statute and/or regulation
and shall apply, as of such required effective date, to the Petreco Plan as if
included therein.

     2. Each Participant of the Petreco Plan as of the Plan Merger Date
(“Petreco Participant”), shall become a Member of the Cooper Cameron Plan as of
such date (if such Petreco Participant is not already a Member of the Cooper
Cameron Plan as of such date).

     3. The trustee of the Petreco Plan shall be directed to transfer the assets
of the Petreco Savings Plan to the trustee of the Cooper Cameron Plan as soon as
administratively feasible after the Plan Merger Date. All assets shall be
transferred in cash, except that outstanding loans from the Petreco Plan to
Petreco Participants shall be transferred in kind. In order to ensure an orderly
transition with respect to the transferred assets of the Petreco Plan, the Plan
Administrator may, in its discretion, temporarily prohibit or restrict
withdrawals, loans, execution of, change to, or revocation of a compensation
deferral election, change of investment designation of plan account balances, or
transfer of amounts in accounts from one investment fund to another investment
fund, or other activity as the Plan Administrator deems appropriate; provided
that any such temporary cessation or restriction of such activity shall be in
compliance with applicable law. Amounts transferred shall initially be invested
in such investment fund or funds available under the Cooper Cameron Plan as
determined by the Plan Administrator in its discretion; provided, however, that
as soon as administratively feasible following the Plan Merger Date, amounts
attributable to accounts of Petreco Participants who are actively participating
in the Cooper Cameron Plan as of the Plan Merger Date shall be invested in
accordance with the respective investment designations on each such Petreco
Participant as in

 

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effect on the date such investment is made. Such transferred amounts shall
remain invested in such fund or funds until the Petreco Participants make new
investment designations with respect to such amounts in accordance with the
provisions of the Cooper Cameron Plan as in effect on the date of such
investment designations.

     4. Amounts credited to Petreco Participants’ accounts under the Petreco
Plan shall be credited to corresponding accounts under the Cooper Cameron Plan
as follows:

  (i)   Amounts, if any, credited to a Petreco Participant’s “Elective
Deferrals” subaccount under his “Participant Account” under the Petreco Plan
shall be credited to such participant’s “Basic Account” under the Cooper Cameron
Plan;     (ii)   Amounts, if any, credited to a Petreco Participant’s “Matching
Contributions” subaccount under his “Participant Account” under the Petreco Plan
shall be credited to such participant’s “Matching Account” under the Cooper
Cameron Plan;     (iii)   Amounts, if any, credited to a Petreco Participant’s
“Discretionary Contributions” subaccount under his “Participant Account” under
the Petreco Plan shall be credited to such participant’s “Profit Sharing
Account” under the Cooper Cameron Plan;     (iv)   Amounts, if any, credited to
a Petreco Participant’s “Rollover Contributions” subaccount under his
“Participant Account” under the Petreco Plan shall be credited to such
participant’s “Rollover/Transfer Account” under the Cooper Cameron Plan; and    
(v)   Amounts, if any, credited to a Petreco Participant’s “Transfer
Contributions” subaccount under his “Participant Account” under the Petreco Plan
shall be credited to such participant’s “Rollover/Transfer Account” under the
Cooper Cameron Plan.

Subaccounts shall be created under the respective Cooper Cameron Plan accounts
for the transferred amounts and earnings thereon (the “Grandfathered
Subaccounts”) in order to preserve optional forms of benefit and rights in
accordance with Paragraphs 7 and 9.

     5. Notwithstanding anything to the contrary in Section 7.5(d) of the Cooper
Cameron Plan, for purposes of determining the Vesting Service under the Cooper
Cameron Plan of a Petreco Participant, (i) such Petreco Participant shall be
credited with Vesting Service on the date he becomes a Member of the Cooper
Cameron Plan with all Years of Service, if any, credited to him for vesting
purposes under the Petreco Plan as of December 31, 2004, (ii) for the period
beginning and ending on January 1, 2005 (the “Computation Period”), such Petreco
Participant shall receive credit equal to the greater of (1) the period of
service that would be credited under the Cooper Cameron Plan for vesting
purposes for such employee’s service during the Computation Period and (2) the
service taken into account for the 2005 Plan Year as of January 1, 2005, under
the method provided in the Petreco Plan for computing Years of Service for
vesting purposes, and (iii) for the period from and after January 2, 2005, such
Petreco Participant shall receive credit based solely upon the provisions of the
Cooper Cameron Plan for

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crediting Vesting Service; provided, however, that if, as of the Plan Merger
Date, the Vesting Service credited to a Petreco Participant pursuant to
Section 7.5(d) of the Cooper Cameron Plan plus the Vesting Service that was
credited to him for the period March 21 through December 31, 2004 under the
terms of the Cooper Cameron Plan (or would have been so credited, had he been a
Member of the Cooper Cameron Plan during such period) is greater than the
Vesting Service credited to a Petreco Participant under clause (i) above, then
such measure of such Petreco Plan Participant’s Vesting Service shall be
substituted in the place of the Vesting Service that would otherwise be credited
under clause (i) above.

     6. For purposes of determining the Participation Service under the Cooper
Cameron Plan of a Petreco Participant who is a Part Time Employee or a Temporary
Employee, a Petreco Participant will be credited with Participation Service
under the provisions of Section 2.1(c) of the Cooper Cameron Plan as if Petreco
International, Inc. (“Petreco”) and its Affiliates were participating Employers
under the Cooper Cameron Plan during the period of such Petreco Participant’s
employment with Petreco and its Affiliates.

     7. Notwithstanding anything to the contrary in the Cooper Cameron Plan,
each Petreco Participants who was employed by Petreco International, Inc. or a
member of its controlled group on January 1, 2002 shall have a 100% fully vested
and nonforfeitable interest in his Profit Sharing Account under the Cooper
Cameron Plan.

     8. Immediately after the merger and transfer of assets described in
Paragraphs 1 and 3 above, each Petreco Participant who becomes or continues to
be a Member of the Cooper Cameron Plan shall, in the event the Cooper Cameron
Plan is then terminated, be entitled to a benefit which is equal to or greater
than the benefit to which such participant would have been entitled under the
Petreco Plan and, if applicable, the Cooper Cameron Plan immediately prior to
such transfer if the Petreco Plan and, if applicable, the Cooper Cameron Plan
had then been terminated. The provisions of the preceding sentence shall be
construed under applicable federal regulations pursuant to Section 208 of the
Employee Retirement Income Security Act of 1974 and Section 414(l) of the
Internal Revenue Code of 1986, as amended (the “Code”).

     9. With respect to the Grandfathered Subaccounts of Petreco Participants,
the Cooper Cameron Plan shall preserve all optional forms of benefit and rights
required to be preserved pursuant to Section 411(d)(6) of the Code, and any
Treasury regulations issued thereunder, as amended from time to time, including,
but not limited to, the optional forms of benefit and rights described on
Appendix A hereto.

     10. The loan procedures available to Members under Article IX of the Cooper
Cameron Plan, shall be applicable to a Petreco Participant’s vested interest in
his Separate Accounts under the Cooper Cameron Plan; provided, however, that any
loan made to a Petreco Participant under the Petreco Plan before the Plan Merger
Date shall be administered by the Plan Administrator in accordance with
Section 12.9 of the Petreco Plan and the loan policy adopted pursuant thereto.

     11. The beneficiary designations of each Petreco Participant in effect
under the Petreco Plan on the Plan Merger Date shall remain in effect under the
Cooper Cameron Plan unless and until such participant executes a new beneficiary
designation in accordance with the provisions of the Cooper Cameron Plan;
provided, however, that all Account balances in the Cooper Cameron Plan from and
after the Plan Merger Date (including amounts transferred from

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the Petreco Plan) shall be subject to any beneficiary designation executed by a
Petreco Participant who was also a Member of the Cooper Cameron Plan prior to
the Plan Merger Date, regardless of whether such beneficiary designation was
executed before the Plan Merger Date, unless and until such time as such Petreco
Participant executes a new beneficiary designation form under the Cooper Cameron
Plan; and provided further, however, that if the preceding proviso applies to a
Petreco Participant, any beneficiary designation executed by such Participant
under the Petreco Plan prior to the Plan Merger Date shall become null and void
as of the Plan Merger Date.

     12. To the extent any forfeitures of Matching Employer Contributions or
Discretionary Employer Contributions under the Petreco Plan exist as of the Plan
Merger Date, such forfeitures shall be applied to offset Employer contribution
obligations for Petreco Participants under the Cooper Cameron Plan.

     13. Each capitalized term used in this instrument shall have the meaning
ascribed to such term under the Petreco Plan or the Cooper Cameron Plan, as
applicable, unless otherwise defined herein.

     14. Except to the extent required under applicable law, the benefits and
rights of any Petreco Participant who terminates employment prior to the Plan
Merger Date shall be governed by the terms and provisions of the Petreco Plan as
in effect on the date of such termination of employment.

     15. As to affected individuals, the Cooper Cameron Plan is hereby amended
to reflect and incorporate the provisions of this instrument. Any provision of
the Petreco Plan or the Cooper Cameron Plan which is inconsistent with any
provision of this instrument shall be considered to be and hereby is amended by
this instrument.

     EXECUTED this 20th day of January, 2005, effective for all purposes as
provided above.

            COOPER CAMERON CORPORATION
                /s/ Jane Schmitt      
By:____________________________________________      Title:   Jane Schmitt     
Name:   VP, Human Resources     

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APPENDIX A
to
MERGER OF THE
PETRECO INTERNATIONAL, INC.
401(k) PROFIT SHARING PLAN
WITH AND INTO THE
COOPER CAMERON CORPORATION
RETIREMENT SAVINGS PLAN

This Appendix A shall apply to the Grandfathered Subaccounts of Petreco
Participants in lieu of certain otherwise applicable provisions of the Cooper
Cameron Plan. To the extent the provisions of this Appendix A conflict with
other provisions of the Cooper Cameron Plan, this Appendix A shall control with
respect to the Grandfathered Subaccounts of Petreco Participants.

     1. Rollover and Transfer Account Withdrawals. In addition to the withdrawal
rights contained in Article VIII of the Cooper Cameron Plan, Petreco
Participants may withdraw all or any part of their Grandfathered Subaccounts (to
the extent vested) under their Rollover/Transfer Accounts under the Cooper
Cameron Plan at any time.

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