Stern Defense AR-15 9mm Conversion Adapter uses 92 Beretta pistol magazines which you may already have a supply of. Stern Defense make two differ models of their Conversion Adapter, just insert like an magazine and it is installed into any mil-spec AR-15 lower receiver in seconds, incorporates a last-round bolt hold open feature. Each adapter is machined from aluminum and requires the use of a 9mm barrel and a Glock-cut bolt. Comes with wrenches to tight up and instructions. Also a 30round 92 aftermarket magazine. All like new.