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                                                                    EXHIBIT 10.4

                                NEN HOLDING INC,
                                549 Albany Street
                           Boston, Massachusetts 02118

December 15, 1997

Ms., Margaret C. Turner
596 Route 34
East Chatham, NY 120

Dear Margaret:

This letter extends, an offer to you to become the Senior Vice President Human
Resources of NEN Life Science Products (NEN or "the Company"). It is clear that
you bring the scope, talent and experience necessary to lead the HR function of
our company in the years ahead. Please consider this document a conveyance of
the basic terms and agreements of our offer.

POSITION RESPONSIBILITY

Senior Vice President Human Resources with full responsibility and
accountability for Organizational Development, all human resources programs and
procedures, and internal/external communications.

Your official start date of these duties will be January 5, 1998.

SALARY

The minimum base salary of your position will be $165,000 per annum, which shall
be paid in installments on a bi-weekly basis. The Company shall review your
performance on each anniversary of your date of hire and at its sole discretion
may increase your base salary for the position based on your performance and die
financial condition of the Company at that time.

BONUS AND INCENTIVE COMPENSATION

A copy of the executive bonus plan entitled "Annual Incentive Plan" will be sent
to you in the next few days and I will be pleased to review it with you. Central
to that discussion will be the Company's budgeted EBITDA, a performance
measurement on which the incentive plan is based. In 1998, the EBITDA budget is
approximately $20.0 million. The design of our plan contains the following key
elements:

     (1)  Threshold for payment of any bonuses is corporate performance of 85%
          of the EBITDA budget.

     (2)  Target bonuses are paid upon achieving 110% of the EBITDA budget.

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Margaret C. Turner
December 15, 1997
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     (3)  Bonuses are not capped.

     (4)  The plan incorporates an increasing percentage of payout as Company
          performance progresses from threshold to budget to 110% of budget and
          beyond.

     (5)  At 110% of budget, your bonus would be 40% of salary,

     (6)  The bonus for each individual will be split between corporate
          performance and personal objectives, with the greatest weight given to
          corporate performance.

Your minimum guaranteed bonus for 1998 will be $25,000. If your performance and
payout as measured by the annual incentive plan exceed the guaranteed amount you
will receive the higher of the two figures for your payout.

EQUITY PARTICIPATION

You are invited to co-invest with myself and Genstar Capital Partners II, L.P.
("Genstar") in NEN. We offer you the opportunity to invest up to $150,000 in the
Company. We will enter into a Stockholders' Agreement outlining the rights and
responsibilities of the shareholders. All shareholders will be subject to
dilution for such things as the proposed stock option plan.

STOCK OPTIONS

The Board of Directors of NEN has established a Stock Option Plan setting aside
ten percent (10%) of the stock of the Company on a fully diluted basis.
Coincident with your employment, the Company will grant you an option of 250
shares at a grant price to be determined by the Board. The plan has a ten (10)
year life and a five (5) year vesting schedule in equal twenty percent (20%)
increments on each anniversary date of the grant. Further grants of stock
options to you would be made annually at the Board's discretion based upon your
and the Company's performance.

Should there be a significant change whereby Genstar's nominees no longer
control the Board of Directors ("Change of Control") and you are subsequently
terminated without Cause (see "Severance Agreement" below for definition of
Cause) by the Board of Directors, or you terminate with good reason, within
eighteen (18) months of the Change of Control, all stock options that have been
granted to you will vest immediately.

BENEFITS

You shall be entitled to participate in the Company's benefit plans, including
group health and medical insurance plans, as they are adopted from time to time
beginning on the first day of your employment. Description of these plans will
be sent under separate cover and someone will be available to provide further
explanation. You shall be entitled to four (4) weeks paid vacation per year.

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Margaret C. Turner
December 15, 1997
Page 3

PENSION AND 401K SAVINGS PLAN

You will be eligible to join the pension plan and 401K savings plan of NEN. Both
of these plans are similar to those provided to the employees of NEN by DuPont.
NEN has contractually agreed with DuPont to maintain a benefits package
"substantially similar" to the current DuPont benefits package for a period of
three (3) years from the date of closing.

SEVERANCE AGREEMENT

NEN will provide protection for you in the event of your termination for reasons
other than Cause. If you are terminated without Cause or if you resign for good
reason, you will receive one (1) year's base salary and eighteen (18) months
continuation of benefits. Attached as Schedule A is a definition of Cause and
Resignation without Good Reason.

EXPENSE REIMBURSEMENT

The Company will reimburse you for reasonable and necessary business expenses
incurred while performing your duties as described in this letter, subject to
the policies, procedures and controls that the Company may from time to time
adopt. Expense reimbursement will be subject to the approval of the CEO. The
Company will pay your relocation expenses according to policy. If, in addition,
NEN fails to perform according to our agreement, NEN will reimbursement you for
your legal fees and expenses in connection with resolution of the dispute.

SUCCESSORS: BINDING AGREEMENT

This agreement shall not be terminated by any merger or consolidation of the
transfer of all or substantially all of the assets of NEN. In the event of such
transaction, the provisions of the agreement shall be binding on the surviving
entity. NEN will cause any successor to assume all of the obligations of the
agreements. Failure to obtain such assumption prior to the effective date of the
merger or consolidation shall constitute Good Reason hereunder and entitle you
to terminate your employment and receive the compensation and benefits as
contained in this agreement.

If you should die while any amounts payable to you were owing had you continued
to live, those amounts will be payable to such persons as you appoint in
writing, or if no such persons are appointed, to your estate.

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Margaret C. Turner
December 15, 1997
Page 4

INDEMNIFICATION

The Company will indemnify you to the fullest extent permitted by law for any
liability incurred as a result of the conduct of your duties as an officer of
NEN.

Margaret, I believe that NEN will provide an excellent opportunity for your next
challenge. I am extending this offer to you to become our Vice President Human
Resources in good faith, and I look forward to a long and close working
relationship with you.

Sincerely,

/s/ John L. Zabriskie
John L. Zabriskie
Chairman, President and Chief Executive Officer

Attachment

Accepted this 16th day of December, 1997.

/s/ Margaret C. Turner
______________________________________
Margaret C. Turner

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                                                                      SCHEDULE A

     SECTION 1. Termination of Employment. (a) Termination for Cause;
Resignation Without Good Reason. (i) If the Executive's employment is terminated
by the Company for Cause (as defined below), or if the Executive resigns from
his employment hereunder, other than for Good Reason (as defined below), the
Executive shall be entitled to only (A) severance benefits as provided by the
Company's general procedures and practices applicable to all employees
terminated in like circumstances, if any, and (B) payment of the pro rata
portion of the Executive's salary through and including the date of termination
or resignation.

     (ii) For purpose of this Agreement, termination for "Cause" shall mean
termination of the Executive's employment by the company because of (A) the
Executive's conviction for, or guilty plea to, a felony or a crime involving
moral turpitude; (B) the Executive's commission of an act of willful gross
misconduct resulting in material harm to the Company; or (C) the executive's
willful and repeated failure, after written notice, to follow the written
policies of the Company as established by the board of the directors of the
Company ("the Board").

     (iii) For purposes of this Agreement, resignation for "Good Reason " shall
mean the resignation of the Executive after (A) notice in writing is given him
of his relocation, without the Executive's consent, to a place of business more
than 35 miles outside of the Boston Metropolitan Statistical Area (B) A
reduction in the Executive's benefits or pay or (C) a substantial adverse
alternation occurs in the nature or status of the Executive's responsibilities
from those in effect on the date hereof.

     (iv) The date of termination for Cause shall be the date of receipt by the
Executive of written notice of such termination. The date of resignation without
Good Reason shall be the date of receipt by the Company of a written notice of
such resignation.<PAGE>   1
                                                                    EXHIBIT 10.6

                             MANAGEMENT ADVISORY AND
                          CONSULTING SERVICES AGREEMENT

          MANAGEMENT ADVISORY AND CONSULTING SERVICES AGREEMENT, dated as of
July 2,1997 (as hereafter amended, modified or supplemented, this "AGREEMENT"),
among NEN HOLDING INC., a corporation organized and existing under the laws of
the State of Delaware ("HOLDINGS"), NEN LIFE SCIENCE PRODUCTS, Inc., a
corporation organized and existing under the laws of the State of Delaware
(together with Holdings, the "COMPANY"), and GENSTAR CAPITAL LLC, a limited
liability company organized and existing under the laws of the State of Delaware
("GENSTAR"),

                              W I T N E S S E T H:
                              - - - - - - - - - -

          WHEREAS, the Company desires to avail itself of the business
experience and expertise of Genstar in arranging financing, strategic planning,
negotiating, executive recruiting and procuring contracts and other areas of
corporate management; and

          WHEREAS, the Company has requested of Genstar and Genstar has agreed
to provide the Company on an ongoing basis, subject to the terms and conditions
specified herein, with management consulting and advisory services related to
the business affairs of the Company;

          NOW, THEREFORE, in consideration of the foregoing and the mutual
agreements and covenants hereinafter set forth and other good and valuable
consideration, the receipt and adequacy of which are hereby acknowledged, and
intending to be legally bound hereby, the parties hereto hereby agree as
follows.

          SECTION 1. Retention of Genstar. The Company hereby retains Genstar as
its exclusive management and corporate, consultant and Genstar accepts such
retention on the terms and conditions set forth herein.

          SECTION 2. Services. (a) Genstar shall advise the Company concerning
such management matters as relate to strategic planning, proposed financial
transactions, procurement of contracts and other management matters related to
the Company's business and administration, and as to such other matters as the
Company may reasonably request.

          (b)  Genstar shall perform all such services as an independent
contractor to the Company and neither Genstar nor its affiliates nor any of
their respective directors, officers, agents or employees shall be liable for
any advice offered or action taken by it or them in connection with this
Agreement. Genstar shall not be considered an employee, agent or representative
of the Company and will not have any authority to act for or bind the Company
without the Company's prior written consent.

          SECTION 3. Compensation. (a) In consideration of the services provided
by Genstar hereunder, the Company shall pay to Genstar a management consulting
fee of $700,000 per annum (the "Base Fee"), payable in quarterly installments
during the term hereof commencing September 30, 1997. The Base Fee shall
increase by 3% per annum at each anniversary hereof.

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          (b)  The Company shall reimburse Genstar for all reasonable
out-of-pocket costs and expenses incurred by Genstar in connection with the
provision of services hereunder promptly upon receipt of a statement of such
costs and expenses from Genstar.

          (c)  Any amount paid when due under the terms and provisions of this
Agreement shall bear interest at the rate of 10% per annum.

          SECTION 4. Company's Further Obligation. The Company shall in good
faith consider all advice and recommendations of Genstar relating to the subject
matter of this Agreement. Notwithstanding the foregoing, the Company shall not
have any obligation whatsoever to follow or implement any such advice or
recommendation of Genstar.

          SECTION 5. Term and Termination. This Agreement shall commence on the
date hereof and shall continue through the period ending on July 2, 2007;
provided, however, that this Agreement shall terminate on the last day of the
first quarter in which Genstar Capital Partners II, L.P. holds less than 5% of
The common stock, par value $.01 per share, of Holdings at such time
outstanding. In the event this Agreement terminates pursuant to this Section 5,
the annual management consulting fee shall be prorated through and paid on the
date of termination

          SECTION 6. Amendments, Etc. No amendment or waiver of any provision of
this Agreement nor consent to any departure herefrom shall in any event be
effective unless the same shall be in writing and signed by the parties hereto,
and then such amendment, waiver or consent shall be effective only in the
specific instance and for the specific purpose for which given.

          SECTION 7. No Waivers. Except as otherwise provided in this Agreement,
any failure of any of the parties to comply with any obligation, covenant,
agreement or condition herein may be waived by the party entitled to the
benefits thereof only by a written instrument signed by the party granting such
waiver, but such waiver or failure to insist upon strict compliance with such
obligation, covenant, agreement or conditions shall not operate as a waiver of,
or estoppel with respect to, any subsequent or other failure.

          SECTION 8. Notices. All notices, requests, claims, demands and other
communications hereunder shall be in writing and shall be given or made (and
shall be deemed to have been duty given or made upon receipt) by delivery in
person, or by courier service, cable, telecopy, telegram, or registered or
certified mail (postage prepaid, return receipt requested) to the respective
parties hereto at their addresses set forth on the signature pages to this
Agreement (or at such other address for a party hereto as shall be specified in
a notice given in accordance with this Section 8).

          SECTION 9. Assignment. Neither of the parties hereto shall have the
right to assign this Agreement or the rights or obligations hereunder.

          SECTION 10. Headings. The headings contained in this Agreement are for
reference purposes only and shall not affect in any way the meaning or
interpretation of this Agreement.

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          SECTION 11. Severability. Any provision of this Agreement which is
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction,
be ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining provisions hereof or affecting the validity or
enforceability of such provision in any other jurisdiction.

          SECTION 12. Entire Agreement. This Agreement constitutes the entire
agreement between the parties hereto with respect to the subject matter hereof
and supersedes all prior agreements and understandings, both written and oral,
between the parties hereto with respect to the subject matter hereof.

          SECTION 13. Governing Law. This Agreement shall be governed by, and
construed in accordance with, the laws of the State of Delaware.

          SECTION 14. Counterparts. This Agreement may be executed in two or
more counterparts, each of which when executed shall be deemed to be an
original, but all of which taken together shall constitute one and the same
agreement.

              [THE REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK]

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          IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the date first above written.

                                         NEN HOLDING INC,

                                             /s/ [signature]
                                         By: ___________________________________
                                             Name:
                                             Title:

                                             /s/ [signature]
                                         By: ___________________________________
                                             Name:
                                             Title:

                                         NEN LIFE SCIENCE PRODUCTS, INC.

                                             /s/ [signature]
                                         By: ___________________________________
                                             Name:
                                             Title:

                                             /s/ [signature]
                                         By: ___________________________________
                                             Name:
                                             Title:

                                         GENSTAR CAPITAL LLC

                                             /s/ [signature]
                                         By: ___________________________________
                                             Name:
                                             Title:

                                             /s/ [signature]
                                         By: ___________________________________
                                             Name:
                                             Title:

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