<PAGE>   1
                                                                   EXHIBIT 10.42

                              EMPLOYMENT AGREEMENT


     THIS EMPLOYMENT AGREEMENT (this "Agreement") is hereby made and entered
into as of the 1st day of May 1998, by and between SLI, Inc., and Oklahoma
corporation (the "Employer"), and Richard F. Parenti, a resident of the State of
Illinois (the "Employee").


                                  WITNESSETH:


1.   EMPLOYMENT. The Employer hereby employs the Employee and the Employee
hereby accepts such employment, upon the terms and subject to the conditions
set forth in this Agreement.

2.   TERM. The term of the employment under this Agreement shall be for a four
year period beginning as of May 1, 1998 and terminating on April 30, 2002,
unless such employment is otherwise terminated as provided in paragraphs 8 and
9 of this Agreement.

3.   COMPENSATION; REIMBURSEMENT, ETC.

     (a)   The basic compensation to the Employee shall be payable bi-weekly
based upon a calendar-year annual base salary of $125,000 (the "Annual Base
Salary"). Such salary shall be subject to an annual performance review but any
adjustment shall not result in an annual salary less than the Annual Base
Salary. Employee shall also be reimbursed for all reasonable expenses incurred
on behalf of Employer.

     (b)   The Employee shall be entitled to such other benefits as the Board
of Directors and/or the Compensation and Stock Option Committee may from time
to time provide to him.

     (c)   Employer has previously granted to Employee an option to purchase
75,000 shares of the Company's Common Stock. In the event Employer terminates
the employment of employee for any reason other than those specified in 9(a) or
if employee terminates his employment pursuant to 9(c) all outstanding options
will immediately vest.

4.   DUTIES. The Employee is engaged as the Vice President of Finance of the
Employer, and he shall have such duties consistent with such office as may from
time to time be reasonably assigned to him by the Board of Directors of the
Employer and provided for in the bylaws of the Employer. Employee's office
shall be located at the Employer's facilities in Hoffman Estates, Illinois.

5.   EXTENT OF SERVICES. During the term of his employment under this
Agreement, the Employee shall devote such time and efforts to the business of
the Employer as may be reasonably necessary in the normal course of business.
Employee agrees, if needed, to spend an average of at least four days per month
at the Company's headquarters in Canton, Massachusetts.

6.   VACATION AND DAYS OFF. The Employee shall be entitled to such vacation
time during each fiscal year of the Employer as he may qualify for, in
accordance with any vacation policy from time to time established by the
Employer's Board of Directors. Notwithstanding the foregoing, the Employee
shall be entitled to an annual vacation period of not less than three (3)
weeks, during which time his compensation shall be paid in full.
<PAGE>   2
7.   DISABILITY, ILLNESS AND INCAPACITY.

     (a)   During the term of this Agreement, for any period of disability,
illness or incapacity which renders the Employee at least temporarily unable to
perform the services required under this Agreement, the Employee shall receive
his full compensation as set forth in paragraph 3 of this Agreement, provided
however, if the Employees disability, illness or incapacity extends beyond a
period of ninety (90) consecutive days, the Employee shall not be entitled,
after the expiration of such ninety (90) day period, to any further
compensation under paragraph 3(a) until he returns to full-time service
hereunder, but he shall be entitled only to such disability payments as may be
provided by any disability insurance policy or policies, purchased by the
Employer.

     (b)   Successive periods of disability, illness or incapacity will be
considered separate periods unless the later period of disability, illness or
incapacity is due to the same or related cause.

     (c)   If and when the period of disability, illness or incapacity of the
Employee totals 90 days, his employment with the Employer shall terminate.
Notwithstanding the foregoing, if the Employee and the Employer agree, the
Employee may thereafter be employed by the Employer upon such terms as may be
mutually agreeable.

     (d)   Any dispute regarding the existence, extent or continuance of the
disability, illness or incapacity shall be resolved by the determination of a
majority of three competent doctors who are not employees of the Employer, one
of which shall be selected by the Employer, one of which shall be selected by
the Employee and a third selected by the other two doctors. The doctors' fees
and other charges associated with such determination shall be paid by the
Employer.

8.   DEATH.
     
     (a)   All rights of the Employee hereunder shall terminate upon his death,
except that the Employer shall pay to the estate of the Employee such
compensation and other amounts as would otherwise have been payable to the
Employee through the end of the month in which his death occurs. The Employer
shall have no additional financial obligation under this Agreement to the
Employee or his estate.

9.   OTHER TERMINATIONS.

     (a)   The Employer may terminate the employment of the Employee hereunder
without notice for any of the following reasons:

           (i)   Employee's failure to promptly and adequately perform the
     duties assigned to him by the Employer pursuant to paragraph 4 above,
     including but not limited to failure to follow the reasonable direction of
     the Board of Directors of the Employer, or of any supervisors or superiors
     of Employee;

           (ii)  Employee's material breach of any provision of this Agreement;
     or

           (iii) other good cause (as defined below).

     (b)   The term "good cause" as used in this Agreement shall include, but
shall not necessarily be limited to, habitual absenteeism, a pattern of conduct
which tends to hold the Employer up to ridicule in the community, conviction of
any crime of moral turpitude abuse of and substantial dependence on, as
reasonably determined by the Board of Directors of the Employer, on any
addictive substance, including but not limited 


                                       2
<PAGE>   3
to alcohol, amphetamines, barbiturates, methadone, cannabis, cocaine, PCP, THC,
LSD or illegal or narcotic drugs. If any determination of abuse and substantial
dependence by the Board of Directors is disputed by the Employee, the parties
hereto agree to abide by the decision of a panel of three physicians who are
not employees of the Employer, one of which shall be selected by the Employer,
one of which shall be selected by the Employee and a third selected by the
other two (2) doctors. The Employee agrees to make himself available for and
submit to examinations by such physicians as may be directed by the Employer.
Failure to submit to any such examination shall constitute a breach of a 
material part of this Agreement. The doctors' fees ad other charges associated
with such determination shall be shared equally by the Employer and the
Employee.

     (c)   Employee may terminate this Agreement for "Good Reason" which shall
result from (i) the Employee is requested to relocate to a facility more than
35 miles from Chicago, Illinois or (ii) the Employer's material breach of any
of its obligations under this Agreement.

     (d)   If the Employee's employment with the Employer is terminated
pursuant to paragraph 9(a), the Employer shall pay to the Employee any
compensation earned but not paid to the Employee prior to such termination.
Such payment shall be in full and complete discharge of any and all liabilities
or obligations of the Employer to the Employee hereunder, and the Employee
shall be entitled to no further benefits under this Agreement, except as
otherwise specifically provided in paragraph 3 of this Agreement. If the
Employee's employment with Employer is terminated by Employer for a reason
other than as set forth under paragraph 9(a) or by Employee pursuant to
paragraph 9(c), Employer will compensate Employee as severance pay the monies
due Employee for the remainder of the term of this Agreement. The severance
will be payable in full at the Employee's current base salary at time of
termination.

10.  CONFIDENTIALITY. The Employee agrees to keep in strict secrecy and
confidence any and all information the Employee assimilates or to which she has
access during his employment by the Employer and which has not been publicly
disclosed and is not a matter of common knowledge in the fields of work of the
Employer. The Employee agrees that both during and after the term of his
employment by the Employer, he will not, without prior written consent of the
Employer, disclose any such confidential information to any third person,
partnership, joint venture, company, corporation or other organization.

11.  WAIVER OR BREACH. The waiver by the Employer of a breach of any of the
provisions of this Agreement by the Employee shall not be construed as a waiver
of any subsequent breach by the Employee.

12.  BINDING EFFECT, ASSIGNMENT. The rights and obligations of the Employer
under this Agreement shall inure to the benefit of and shall be binding upon
the successors and assigns of the Employer. This Agreement is a personal
employment contract and the rights, obligations and interests of the Employee
hereunder may not be sold, assigned, transferred, pledged or hypothecated.

13.  ENTIRE AGREEMENT. This Agreement and the option agreement containing the
terms and provisions of the Employee's Option contains the entire agreement and
supersedes all prior agreements and understandings, oral or written, with
respect to the subject matter hereof. This Agreement may be changed only by an
agreement in writing signed by the party against whom any waiver, change,
amendment, modification or discharge is sought.

14.  HEADINGS. The headings contained in this Agreement are for reference
purposes only and shall not affect the meaning or interpretation of this
Agreement.

15.  GOVERNING LAW. This Agreement shall be construed and enforced in
accordance with the laws of the State of Massachusetts.


                                       3
<PAGE>   4
16.  NOTICES. Any notice required or permitted to be given under this Agreement
shall be sufficient if in writing and if sent by certified or registered mail,
first class, return receipt requested, to the parties at the following address:


     To the Employer:    SLI, Inc.
                         500 Chapman Street
                         Canton, MA 02021


     To the Employee:    Richard Parenti
                         3100 W. Higgins Rd., #190
                         Hoffman Estates, Illinois 60195


     IN WITNESS WHEREOF, the parties hereto have executed this Agreement this
___ day of ____________, 1998.


                                        EMPLOYER:

                                        SLI, INC.
ATTEST:
                                        By:
------------------------------             ------------------------------
                                           Frank M. Ward, President


                                        EMPLOYEE:
Witness as to Employee:

------------------------------          ---------------------------------
                                           Richard F. Parenti



                                       4