The Double Star AR-15 Lower Receiver Parts Kit includes everything needed to complete a stripped AR-15 lower receiver. The Kit includes: Fire control group Fire control group pins and springs Bolt catch assembly Magazine catch assembly Front pivot pin Rear takedown pin Takedown springs (2) Takedown detents (2) Trigger guard pin Pistol grip, screw and washer Buffer detent Buffer detent spring Mfg: Double Star SPECS: Fits small pin AR-15 lower receivers.