ATF approved! Adapter with Rear Blade Pistol Stabilizer for M11 Cobray 9mm Semi Auto. This rear stock adapter is a two piece design cut from the same aluminum as most AR receivers, machined to cradle the receiver for added strength. It has a custom designed inner rear spring spacer that replaces the inner OEM part. This allows the bracket to be bolted to the gun for a great fit. The adapter is finished is black anodize and comes complete with threaded insert, Allen wrench and instructions on installation. This part number for the Adapter, pistol buffer tube and Shockwave Blade, other parts sold separately. ATF letter can be printed from the KAK industries we siteAvailable in FDE color.