All of the parts needed to build out your lower receiver: Lower Part Kits (LPK), Bolt Catch, Bolt Catch Plunger, Bolt Catch Spring, Bolt Catch Roll Pin, Buffer, Buffer Retainer, Buffer Retainer Spring, Buffer Tube, Castle Nut, End Plate, Grip, Grip Screw, Grip Washer, Magazine Catch Body, Magazine Catch Spring, Magazine Release Button, Pivot Pin, Safety Selector, Safety Selector Detent, Safety Selector Detent Spring, Stock, Takedown Pin, Takedown/Pivot Spring, Takedown/Pivot Detent, Trigger, Trigger Guard, Trigger Guard Roll Pin. Mil-Spec. Made in the USA.