This complete Windham Weaponry Lower Receiver Parts Kit will give you everything needed to build up a stripped Lower, or keep your AR functioning in the toughest conditions. All highest quality parts, this kit includes: AR Hammer with J-Pin; Hammer Spring; AR Safety Selector Lever; Safety Detent; Safety Detent Spring; Bolt Catch; Bolt Catch Spring Pin; Bolt Catch Plunger; Bolt Catch Spring; Magazine Catch; Magazine Catch Spring; Magazine Catch Button; Takedown/Pivot Pin Detents (2); Takedown/Pivot Pin Springs (2); Pivot Pin; Takedown Pin; AR Trigger; Trigger Spring; AR Disconnector; Disconnector Spring; Trigger Guard (Aluminum); Trigger Guard Spring Pin; Hammer/Trigger Pins (2); Pistol Grip; Pistol Grip Screw; Pistol Grip Washer; Buffer Retainer; Buffer Retainer Spring.