CMMG's Springs and Pins kit contains some of the most commonly lost components of a lower parts build. If that detent goes flying across the room, CMMG has you covered. Includes: AR-15 Hammer and Trigger Spring AR-15 Hammer and Trigger Pins AR-15 Selector Spring and Detent AR-15 Buffer Retainer and Spring AR-15 Trigger Guard Roll Pin AR-15 Takedown Spring (No Pins) AR-15 Disconnector Spring AR-15 Takedown Detent AR-15 Bolt Catch Roll Pin