Tactical Superiority's AR-15 lower parts kit includes all of the parts needed to assemble a stripped AR-15 lower receiver. This is a US made Mil-Spec parts kit and includes: .556 Takedown Pin, .556 Pivot Pin, Takedown Pin Detent (2), Takedown Pin Detent Spring (2), .556 Bolt Catch, Bolt Catch Plunger, .556 Bolt Catch Screw, Bolt Catch Spring, Buffer Retainer, Buffer Retainer Spring, Hammer & Trigger Pin (2), Hammer Spring, Trigger Spring, Disconnector, Disconnector Spring, Magazine Catch, Magazine Catch Spring, Magazine Catch Button, Trigger Guard Assembly, Trigger Guard Pivot Spring Pin, Safety Selector, Safety Selector Detent, Safety Selector Detent Spring, Pistol Grip Screw, Pistol Grip Screw Lock Washer, Hammer, Trigger, Pistol Grip (Black).