EXHIBIT 99.6
    

                            KNOGO NORTH AMERICA INC.
                             350 Wireless Boulevard
                            Hauppauge, New York 11788


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                    NOTICE OF SPECIAL MEETING OF STOCKHOLDERS
                           TO BE HELD FEBRUARY 6, 1997

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         NOTICE IS HEREBY GIVEN that a Special  Meeting of Stockholders of Knogo
North America Inc. ("Knogo") will be held at Knogo's corporate headquarters, 350
Wireless Boulevard, Hauppauge, New York, on February 6, 1997, at 11:00 a.m., New
York time (the "Knogo Meeting"), for the following purposes:

                  1. To  consider  and vote on a  proposal  (the  "Knogo  Merger
         Proposal") to approve and adopt the Amended and Restated  Agreement and
         Plan of  Reorganization  and Merger,  dated as of November 27, 1996, as
         amended by Amendment  No. 1 to Amended and Restated  Agreement and Plan
         of   Reorganization   and   Merger,   dated  as  of  January  10,  1997
         (collectively, the "Merger Agreement"), among Video Sentry Corporation,
         a   Minnesota   corporation   ("Video"),   Knogo,   Sentry   Technology
         Corporation, a Delaware corporation recently formed to act as a holding
         company  ("Sentry"),  Viking  Merger  Corp.,  a  Minnesota  corporation
         ("Video Merger Corp."),  and Strip Merger Corp., a Delaware corporation
         ("Knogo Merger Corp."), and the transactions contemplated by the Merger
         Agreement, pursuant to which:
    

                           (a) Knogo Merger  Corp.  will be merged with and into
                  Knogo,  leaving Knogo as a  wholly-owned  subsidiary of Sentry
                  (the "Knogo Merger");

                           (b) Video Merger  Corp.  will be merged with and into
                  Video,  leaving Video as a wholly-owned  subsidiary  of Sentry
                  and a sister  corporation  of Knogo (the "Video  Merger"  and,
                  collectively with the Knogo Merger, the "Merger");

                           (c) Each 1.2022 shares of common stock of Knogo,  par
                  value $0.01 per share (the "Knogo Common Stock"),  outstanding
                  at the  effective  time of the Knogo  Merger will be converted
                  into the right to receive merger  consideration in the form of
                  one share of common  stock of  Sentry,  par value  $0.001  per
                  share (the "Sentry  Common  Stock"),  and one share of Class A
                  preferred stock of Sentry, par value $0.001 per share, as more
                  fully    described   in   the    accompanying    Joint   Proxy
                  Statement/Prospectus;

                           (d) Each  share of common  stock of Video,  par value
                  $0.01 per  share,  outstanding  at the  effective  time of the
                  Video  Merger  will be  converted  into the  right to  receive
                  merger consideration in the form of one share of Sentry Common
                  Stock, as more fully described in the accompanying Joint Proxy
                  Statement/Prospectus;

         subject to and as more fully  described  in the Merger  Agreement,  the
         full text of which is attached hereto as Appendix A to the accompanying
         Joint Proxy Statement/Prospectus; and

                  2. To transact such other business as may properly come before
         the Knogo Meeting or any adjournment thereof.

         Only  holders of Knogo  Common Stock of record at the close of business
on January 10, 1997 (the "Knogo  Record  Date") are entitled to notice of and to
vote at the Knogo Meeting or any adjournments or postponements thereof. Approval
of the matters to be voted upon in connection with the Knogo Merger requires the
affirmative




vote of a majority of the  outstanding  shares of Knogo Common Stock entitled to
vote thereon, in person or by proxy, at the Knogo Meeting.

                                           By Order of the Board of Directors,

                                           PETER J. MUNDY
                                           Secretary


   
Hauppauge, New York
January 23, 1997
    


         PLEASE MARK,  SIGN, DATE AND RETURN THE  ACCOMPANYING  FORM OF PROXY AS
         PROMPTLY AS POSSIBLE IN THE ENCLOSED ENVELOPE,  WHETHER OR NOT YOU PLAN
         TO ATTEND  THE KNOGO  MEETING.  YOUR  PROXY MAY BE  REVOKED,  EITHER IN
         WRITING OR BY VOTING IN PERSON AT THE KNOGO MEETING,  AT ANY TIME PRIOR
         TO THE EXERCISE OF THE PROXY.

THE BOARD OF DIRECTORS OF KNOGO UNANIMOUSLY  RECOMMENDS THAT KNOGO  STOCKHOLDERS
VOTE TO APPROVE THE MATTERS TO BE VOTED UPON AT THE KNOGO MEETING.

           PLEASE DO NOT SEND IN ANY SHARE CERTIFICATES AT THIS TIME.