Magpul

:-Compatible with standard mil-spec forged AR15/M16 receivers*-Thin, anti-snag profile & textured surface still allows for traditional manipulation of the bolt catch whilemaintaining unobstructed access to the trigger-Attaches to the existing bolt catch paddle via one screw-Machined from durable billet 6061-T6 aluminum-Finished with MIL-A-8625F, Type III, Class 2 hard anodizing with manganese phosphate on the screw per MIL-DTL-16232G-Torx® mounting screw with Nyloc® Blue patch prevents back out under recoil (Torx wrench included)*NOT compatible with 7.62x51 (.308 Winchester) firearms as well as most AR15 billet or polymer lower & upper receivers due to their larger and/or non-standard dimensions (including the S&W Magpul Spec Series™ lowers)