SERIES B UNITS CONSISTING OF TWO SHARES OF CLASS B COMMON STOCK, ONE CLASS W WARRANT TO PURCHASE ONE SHARE OF COMMON STOCK AND ONE CLASS Z WARRANT TO PURCHASE ONE SHARE OF COMMON STOCK

Exhibit 4.2

CUSIP                                 

SERIES B UNITS CONSISTING OF TWO SHARES OF CLASS B COMMON STOCK, ONE CLASS W WARRANT TO PURCHASE ONE SHARE OF COMMON STOCK AND ONE CLASS Z WARRANT TO PURCHASE ONE SHARE OF COMMON STOCK

Each Series B Unit (“Series B Unit”) consists of two (2) shares of Class B common stock, par value $.0001 per share (“Class B Common Stock”), of Mercator Partners Acquisition Corp., a Delaware corporation (the “Company”), one (1) Class W Warrant (the “Class W Warrant”) and one (1) Class Z Warrant (the “Class Z Warrant”). Each Class W Warrant and Class Z Warrant entitles the holder to purchase one (1) share of common stock, par value $.0001 per share (the “Common Stock”) for $5.00 per share (subject to adjustment). Each Class W Warrant and Class Z Warrant will become exercisable on the later of (a) [              ], 2006 or (b) the earlier of the Company’s completion of a business combination or the distribution of funds held by that certain trust fund on behalf of the holders of the Company’s Class B Common Stock. The Class W Warrants will expire unless exercised before 5:00 p.m., New York City time, on [              ], 2010, or earlier upon redemption, and the Class Z Warrants will expire unless exercised before 5:00 p.m., New York City time, on [              ], 2012, or earlier upon redemption. The Class B Common Stock, Class W Warrants and Class Z Warrants comprising the Series B Units represented by this certificate are not transferable separately prior to [              ], 2005, subject to earlier separation in the discretion of HCFP/Brenner Securities LLC. The terms of the Class W Warrants and the Class Z Warrants are governed by a Warrant Agreement, dated as of [              ], 2005, between the Company and American Stock Transfer & Trust Company