The easiest way to stock and sell genuine, mil-spec AR-15 parts, or use to assemble rifles on your receivers. Much lower in total cost than buying the parts one at a time. Kit includes: single stage trigger, trigger spring, trigger pin, hammer, hammer spring, hammer pin, disconnector and spring, bolt catch, b/c plunger, b/c spring, b/c roll pin, selector, selector detent, selector detent spring, (2) takedown detents and springs, pivot pin, rear takedown pin, buffer retainer and spring, magazine catch, button and spring, A2 pistol grip, screw and washer, triggerguard assembly and pin.