This CMMG AR-15 lower receiver parts kit includes everything needed to build a complete a lower receiver less a stock assembly and stripped lower receiver of your choice. All parts are made to standard military specs. Parts are packaged by group in color coded bags to make assembly easy. Kit Includes: Bolt Catch - Bolt Catch Plunger - Bolt Catch Roll Pin - Bolt Catch Spring - Buffer Retainer - Buffer Retainer Spring - Disconnector - Disconnector Spring - Hammer - Hammer Pin - Hammer Spring - Magazine Catch - Magazine Catch Button - Magazine Catch Spring - Pistol Grip - Pistol Grip Lock Washer - Pistol Grip Screw - Pivot Pin - Pivot Pin Detent - Pivot Pin Detent Spring - Selector - Selector Detent - Selector Detent Spring - Takedown Pin - Takedown Pin Detent - Takedown Pin Detent Spring - Trigger - Trigger Guard - Trigger Guard Roll Pin - Trigger Pin - Trigger Spring