Bushmaster's Lower Parts Kit helps you build your AR-15 Stripped Lower. It is MilSpec dimensions and made with the highest quality for precision and perfection. Includes: Hammer, Hammer Spring, Trigger, Trigger Spring, Hammer & Trigger Pivot Pins (2), Disconnector, Disconnector Spring, Bolt Catch, Bolt Catch Plunger, Pivot Pin, Buffer Retainer, Buffer Retainer Spring, Magazine Catch Button, Magazine Catch Spring, Magazine Catch, Take Down Pin, Selector, Selector Detent, Selector Detent Spring, Trigger Gaurd, Trigger Gaurd Roll Pin, Takedown Detent Pin (2), Takedown Detent Spring (2), Grip Screw, Grip Washer, Pistol Grip