AR15 Armorer's Barrel Wrench, the combo tool with plenty of features to work/upgrade your AR-15/ M4/ M16. Features: AR15 Armorer's barrel wrench Combo tool with plenty of features to work, upgrade your AR-15/M4/M16 Barrel wrench for GI barrel nut A1 and A2 flash suppressor wrenches Older single pin and the newer M4 collapsible stock castle nut wrenches Flat blade screw driver 1/2 inches drive ratchet compatible