Common use of PURCHASE FORM Clause in Contracts

PURCHASE FORM. (To be executed upon exercise of Warrant) The undersigned hereby irrevocably elects to exercise _________ Warrants evidenced by this Warrant Certificate, and herewith tenders in payment for such exercise payment of the Exercise Price in full, in the form of a certified check payable to the order of Houston Biotechnology Incorporated in the amount of $_______, all in accordance with the terms hereof. The undersigned requests that the Warrant Shares or other securities receivable upon exercise be in fully registered form and registered in such name and delivered, together with any other property receivable upon exercise, as specified below. If said number of Warrants exercised is less than all of the Warrants evidenced hereby, the undersigned requests that a new Warrant Certificate representing the remaining Warrants evidenced hereby be issued and delivered as set forth below. Issue to: ______________________________________________ (Name) ______________________________________________ (Address, including zip code) ______________________________________________ (Social security or other identifying number) Deliver to: ______________________________________________ (Name) ______________________________________________ (Address, including zip code) Dated: ___________________ ____________________________________ (Insert social security or other identifying number of Holder) Signature: ____________________ NOTE: Signature must conform in all respects to name of Holder as specified on the face of this Warrant Certificate in every particular, without alteration or enlargement or any change whatsoever, unless this Warrant Certificate has been assigned.

PURCHASE FORM. (To be executed upon exercise of Warrant) To: Eltrax Systems, Inc. The undersigned hereby irrevocably elects to exercise exercises the Warrant for the purchase of _________________ Warrants evidenced by this shares (subject to adjustment) of the common stock, par value $.01 per share, of Eltrax Systems, Inc., for the Warrant Certificate, and herewith tenders in makes payment for such exercise payment of the Exercise Price in full, in the form of a certified check payable to the order of Houston Biotechnology Incorporated in the amount of $____________________ (the "Exercise Price") through the following method: [ ] such payment of the Exercise Price being in cash or by certified or official bank check payable to the order of Eltrax Systems, Inc.; [ ] such payment of the Exercise Price being made by wire transfer of same day funds to Eltrax Systems, Inc. to the account specified in [place account is specified]; [ ] such payment of the Exercise Price made by surrendering of such additional part of the Warrant having an aggregate Spread (as such term is defined in the Warrant) equal to the aggregate Exercise Price; all in accordance with at the Exercise Price and on the terms hereofand conditions specified in the within the Warrant therein referred to, surrenders the Warrant and all right, title and interest therein to Eltrax Systems, Inc. and directs (subject to Section 9 of the Warrant) that the shares of Borrower Common Stock deliverable upon the exercise of such Warrant be registered or placed in the name and at the address specified below and delivered thereto. The undersigned requests hereby certifies to Eltrax Systems, Inc. that it is, at the Warrant Shares or other securities receivable upon time of exercise be of the Warrant, an "accredited investor" as defined in fully registered form and registered in such name and delivered, together with any other property receivable upon exerciseRule 501(a) of the Securities Act of 1933, as specified belowamended. If said number of Warrants exercised is less than all of the Warrants evidenced hereby, the undersigned requests that a new Warrant Certificate representing the remaining Warrants evidenced hereby be issued and delivered as set forth below. Issue toDate: ___________________________________________, 20___ (NameSignature of Owner)2 (Street Address) (City) (State) (Zip Code) ______________________________________________ (Address, including zip code) ______________________________________________ (Social security or other identifying number) Deliver to: ______________________________________________ (Name) ______________________________________________ (Address, including zip code) Dated: ___________________ ____________________________________ (Insert social security or other identifying number of Holder) Signature: ____________________ NOTE: Signature must conform in all respects to name of Holder as specified on the face of this Warrant Certificate in every particular, without alteration or enlargement or any change whatsoever, unless this Warrant Certificate has been assigned.

PURCHASE FORM. (To be executed upon exercise of WarrantTO BE EXECUTED ONLY UPON EXERCISE OF WARRANT) The undersigned hereby irrevocably elects to exercise _________ Warrants evidenced by this Warrant Certificate, and herewith tenders in payment for such exercise payment of the Exercise Price in full, in the form of a certified check payable to the order of Houston Biotechnology Incorporated in the amount of $_______, all in accordance with the terms hereof. The undersigned requests that the Warrant Shares or other securities receivable upon exercise be in fully registered form and registered in such name and delivered, together with any other property receivable upon exercise, as specified below. If said number of Warrants exercised is less than all of the Warrants evidenced hereby, the undersigned requests that a new Warrant Certificate representing the remaining Warrants evidenced hereby be issued and delivered as set forth below. Issue to: exercises ______________________________________________ (Name) ______________________________________________ (Address, including zip code) ______________________________________________ (Social security or other identifying number) Deliver to: ______________________________________________ (Name) ______________________________________________ (Address, including zip code) Dated: ___________________ ____________________________________ (Insert social security or other identifying number of Holder) Signature: ____________________ NOTE: Signature must conform in all respects to name of Holder as specified on the face of Warrants represented by this Warrant Certificate for the purchase of 18.266 shares of Common Stock par value $.01 per share, of Metrocall, Inc. for each such Warrant, herewith tenders payment of the Exercise Price for such shares of Common Stock, in every particularfull, without alteration (a) in the form of a certified or enlargement official bank check or any change whatsoeverwire transfer payable to the order of Metrocall, unless Inc. or a combination thereof, (b) such number of shares of the Company's Series A Convertible Preferred Stock par value $.01, having an aggregate stated value plus accrued and unpaid dividends equal to the aggregate Exercise Price, in the amount of $ , (c) by foregoing such number of shares receivable upon exercise of such Warrants with an aggregate Current Market Price equal to the aggregate Exercise Price for such shares of Common Stock or (d) a combination of clauses (a), (b) or (c) above, all in accordance with the terms of the within Warrant Certificate and the Warrant Agreement referred to therein (the "Warrant Agreement"), surrenders this Warrant Certificate has been assigned.and all right, title and interest herein, and directs that the shares of Common Stock deliverable upon exercise of the Warrants and a Warrant Certificate for the remaining Warrant(s), if any, be registered or placed in the name(s) and at the addressees) specified below and delivered thereto. Dated: , 19 ----------------- -- (1) ---------------------------- (Signature of Owner) ------------------------------ (Street Address) ------------------------------- (City) : (State) (Zip Code) Signature Guaranteed by: ------------------------------- ------------------