CMMG Lower Receiver Parts Kit, 223 Rem/556NATO, Black Finish, Includes Takedown Pin, Receiver Pivot Pin, Takedown Pin Detent (2), Takedown Pin Detent Spring (2), Hammer and Trigger Pin (2), Hammer Spring, Trigger Spring, Disconnect, Disconnect Spring, Ambi Safety Selector, Selector Detent, Lock Washer, Pistol Grip Screw, Hammer, Trigger, Pistol Grip, Magazine Catch, Magazine Catch Spring, Magazine Release Button, Trigger Guard Assembly, Bolt Catch, Bolt Catch Plunger, Bolt Catch Spring Pin, Bolt Catch Spring, Buffer Retainer, Buffer Retainer Spring 55CA6B8.