Warhead 9mm Carbine Conversion Kit.  This kit will convert any M4 or M16 variant gun to take UZI 9mm style magazines!  Will work with any Marui style UZI hicap or lowcap magazine with a small modification to the back of the mag.  After the modification, it will still work in Marui guns as before, so no damage is done.  This great kit gives your M4 or M16 a very unique look!  Convert your M4 into a "Commando" type CQB weapon.  Fun and easy to use.  Just pop the kit into the mag well and start enjoying UZI magazines!