Parts included in this are as follow parts: Nitromet Bolt Catch, Plunger, Buffer Retainer, NiB-X Disconnect, Nitromet Magazine Catch, Nitromet Magazine Release Button,Trigger Guard Assembly, Nitromet Safety Selector, Selector Detent,Lock Washer, Pistol Grip Screw, NiB-X Hammer, NiB-X Trigger.