J.P. MORGAN SECURITIES INC.                            THE BEACON GROUP CAPITAL SERVICES, LLC
                 60 WALL STREET                                       399 PARK AVENUE, 17TH FLOOR
               NEW YORK, NY 10260                                          NEW YORK, NY 10022
                 (877) 869-0656                                              (212) 339-9100


                           OFFER TO PURCHASE FOR CASH

                     ALL OUTSTANDING SHARES OF COMMON STOCK
                                       OF
                          METRIKA SYSTEMS CORPORATION
                                       AT
                              $9.00 NET PER SHARE
                                       BY
                            METRIKA ACQUISITION INC.
                          A WHOLLY-OWNED SUBSIDIARY OF
                         THERMO INSTRUMENT SYSTEMS INC.

  THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY
        TIME, ON THURSDAY, APRIL 27, 2000, UNLESS THE OFFER IS EXTENDED.

                                                                  March 31, 2000

To Brokers, Dealers, Commercial Banks,
    Trust Companies and Other Nominees:

    We have been appointed by Metrika Acquisition Inc., a Delaware corporation
(the "Purchaser") and a wholly-owned subsidiary of Thermo Instrument
Systems Inc., a Delaware corporation ("Thermo Instrument"), to act as Dealer
Managers in connection with the Purchaser's offer to purchase all outstanding
shares of common stock, par value $0.01 per share (the "Shares"), of Metrika
Systems Corporation, a Delaware corporation (the "Company"), at a purchase price
of $9.00 per Share, net to the seller in cash, without interest thereon, upon
the terms and subject to the conditions set forth in the Offer to Purchase dated
March 31, 2000 (the "Offer to Purchase") and in the related Letter of
Transmittal (which, together with any amendments or supplements thereto,
collectively constitute the "Offer") enclosed herewith.

    THE OFFER IS CONDITIONED UPON, AMONG OTHER THINGS DESCRIBED IN THE OFFER TO
PURCHASE, THERE BEING VALIDLY TENDERED AND NOT WITHDRAWN PRIOR TO THE EXPIRATION
OF THE OFFER THAT NUMBER OF SHARES WHICH, TOGETHER WITH SHARES OWNED BY THERMO
ELECTRON CORPORATION AND ITS SUBSIDIARIES, INCLUDING THERMO INSTRUMENT,
CONSTITUTES AT LEAST NINETY PERCENT (90%) OF THE OUTSTANDING SHARES ON THE
EXPIRATION DATE (AS DEFINED IN THE SECTION OF THE OFFER TO PURCHASE CAPTIONED
"THE TENDER OFFER--TERMS OF THE OFFER; EXPIRATION DATE"). THE OFFER IS ALSO
SUBJECT TO OTHER IMPORTANT TERMS AND CONDITIONS CONTAINED IN THE OFFER TO
PURCHASE.

    Enclosed for your information and for forwarding to your clients for whose
accounts you hold Shares registered in your name or in the name of your nominees
are copies of the following documents:

    1.  The Offer to Purchase dated March 31, 2000.

    2.  The Letter of Transmittal to tender Shares (for your use and for the
       information of your clients).

    3.  The Notice of Guaranteed Delivery for Shares (to be used to accept the
       Offer if certificates evidencing Shares ("Share Certificates") are not
       immediately available or if such Share Certificates and all other
       required documents cannot be delivered to American Stock Transfer & Trust
       Company (the "Depositary") prior to the Expiration Date or if the
       procedures for book-entry transfer cannot be completed on a timely
       basis).

    4.  A printed form of letter that may be sent to your clients for whose
       accounts you hold Shares registered in your name or in the name of your
       nominees, with space provided for obtaining such clients' instructions
       with regard to the Offer.

    5.  Guidelines for Certification of Taxpayer Identification Number on
       Substitute Form W-9.

    6.  A return envelope addressed to the Depositary.

    YOUR PROMPT ACTION IS REQUESTED. WE URGE YOU TO CONTACT YOUR CLIENTS AS
PROMPTLY AS POSSIBLE. PLEASE NOTE THAT THE OFFER AND WITHDRAWAL RIGHTS WILL
EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, ON THURSDAY, APRIL 27, 2000,
UNLESS THE OFFER IS EXTENDED.

    In all cases, payment for Shares tendered and accepted for payment pursuant
to the Offer will be made only after timely receipt by the Depositary of
(i) certificates evidencing Shares ("Share Certificates") or timely confirmation
of a book-entry transfer of such Shares into the Depositary's account at the
Book-Entry Transfer Facility (as defined in the section of the Offer to Purchase
captioned "The Tender Offer--Acceptance For Payment And Payment For Shares")
pursuant to the procedures set forth in the section of the Offer to Purchase
captioned "The Tender Offer--Procedures For Accepting The Offer And Tendering
Shares," (ii) the Letter of Transmittal (or a facsimile thereof), properly
completed and duly executed, with any required signature guarantees, or an
Agent's Message (as defined in the section of the Offer to Purchase captioned
"The Tender Offer--Acceptance For Payment And Payment For Shares") in connection
with a book-entry transfer, and (iii) any other documents required by the Letter
of Transmittal.

    If a stockholder desires to tender Shares pursuant to the Offer and such
stockholder's Share Certificates are not immediately available or such
stockholder cannot deliver the Share Certificates and all other required
documents to reach the Depositary prior to the Expiration Date, or such
stockholder cannot complete the procedure for delivery by book-entry transfer on
a timely basis, such Shares may nevertheless be tendered by following the
guaranteed delivery procedures specified in the section of the Offer to Purchase
captioned "The Tender Offer--Procedures For Accepting The Offer And Tendering
Shares."

    No fees or commissions will be paid to brokers, dealers or any other persons
(other than to the Dealer Managers and D.F. King & Co., Inc. (the "Information
Agent"), as described in the Offer to Purchase) for soliciting tenders of Shares
pursuant to the Offer. The Purchaser will, however, upon request, reimburse you
for customary mailing and handling expenses incurred by you in forwarding any of
the enclosed materials to your clients.

    The Purchaser will pay or cause to be paid any transfer taxes payable on the
purchase of Shares by the Purchaser pursuant to the Offer, except as otherwise
provided in Instruction 6 of the Letter of Transmittal.

    Questions and requests for assistance or for additional copies of the
enclosed materials may be directed to the Dealer Managers or the Information
Agent, at their respective addresses and telephone numbers set forth on the back
cover of the Offer to Purchase.

                                         Very truly yours,

                                         J.P. Morgan Securities Inc.
                                         The Beacon Group Capital Services, LLC

    NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE YOU
OR ANY OTHER PERSON THE AGENT OF THERMO ELECTRON CORPORATION OR ANY OF ITS
SUBSIDIARIES (INCLUDING WITHOUT LIMITATION THERMO INSTRUMENT AND THE PURCHASER),
THE COMPANY, THE DEALER MANAGER, THE DEPOSITARY OR THE INFORMATION AGENT, OR ANY
AFFILIATE OF ANY OF THEM, OR AUTHORIZE YOU OR ANY OTHER PERSON TO MAKE ANY
STATEMENT OR USE ANY DOCUMENT ON BEHALF OF ANY OF THEM IN CONNECTION WITH THE
OFFER OTHER THAN THE ENCLOSED DOCUMENTS AND THE STATEMENTS CONTAINED THEREIN.