Colt's Manufacturing, Field Repair Kit, For AR15/M4, Black, Comes With Ring Bolt, Trigger Spring, Hammer Spring, Bolt Catch Roll Pin, Bolt Catch Spring, Disconnect Spring, Bolt Catch Plunger, Hammer Pin Retainer, Magazine Catch Spring, Hammer & Trigger Pin, Spring Detent Takedown Pin, Detent Takedown Pin, Fire Control Selector Detent, Ejector And Safety Detent Spring, Buffer Retainer, Buffer Retainer Spring, Takedown Pin, Firing Pin, And Firing Pin Retaining Pin.