Daniel Defense Castle Nut Black 15-057-20039

The Daniel Defense Castle Nut will secure your mil spec or commercial spec carbine receiver extension and rear receiver end plate to the lower receiver. Made with recesses for staking your rear receiver end plate to prevent the castle nut from coming loose.  It is finished with a heavy magnesium phosphate coating and is compatible with common armorers/castle nut wrenches (not included). Weight: 0.5 oz.