Spike's Tactical Lower Receiver Parts Kit Without Fire Control Group/Trigger Group - 223 Rem/556NATO - Includes Safety Selector - Bolt Catch - Magazine catch - Billet Magazine Catch Button - Front Pivot Pin - Rear Take Down Pin - Aluminum Trigger Guard w/Spring Loaded Detent - Bolt Catch Spring - Disconnect Spring - Magazine Catch Spring - Safety Selector Spring - Buffer Retainer Spring - Safety S