NcSTAR AR15 Crows Foot Lower Pro Tool, For Use on AR15 Castle Nut and A2 Buffer Tube Wrench, Steel Construction, Matte Finish, Black VTARCFLWRPRO The Crows Foot PRO tool for AR15 Buffer Tubes provides AR15/ M4 Castle Nut spanner wrenches for telescoping stock tubes" AR15 Rifle A2 buffer tube wrench" Flat blade screwdriver for securing A2 buttstock plate screws" and 1/2" and 3/8" drive compatible.