Re: Cancellation of Certain Common Stock Purchase Warrants

                            LAURUS MASTER FUND, LTD.
                       c/o M&C Corporate Services Limited
                                 P.O. Box 309 GT
                                  Ugland House
                               South Church Street
                                   George Town
                          Grand Cayman, Cayman Islands

                                                                     Exhibit 4.2


                                                                   June 30, 2006

Greenman Technologies, Inc.
7 Kimball Lane

Building A
Lynnefield, MA 01940

Attn: Chief Financial Officer

            Re: Cancellation of Certain Common Stock Purchase Warrants

      Reference is made to (i) that certain Amended and Restated Security and
Purchase Agreement, dated as of June 30, 2004 and amended and restated as of the
date hereof (as amended, restated, modified and/ or supplemented from time to
time, the "Security Agreement"), by and among GreenMan Technologies, Inc., a
Delaware corporation (the "Parent"), certain subsidiaries of the Parent set
forth on Exhibit A hereto (the Parent, together with such subsidiaries,
collectively, the "Companies" and each, a "Company") and Laurus Master Fund,
Ltd. (the "Purchaser"), (ii) the Common Stock Purchase Warrant, issued as of the
date hereof and and exercisable into up to 3,586,429 shares of Common Stock (as
amended,