The Seekins Precision 0011510063 Enhanced Builders Kit is an AR-15 lower parts kit containing pins, springs, and other components required to assemble a lower receiver. In this kit you will receive an Enhanced Bolt Catch, Bolt Catch Roll Pin, Bolt Catch Spring, Bolt Catch Plunger, Buffer Retainer Pin, Buffer Retainer Spring, Mag Release Button, Mag Catch, Mag Catch Spring, a Safety Selector Barrel with both 60/90 degree options, a Short Safety Selector Lever, a Long Safety Selector Lever, Selector Detent, Selector Spring, Trigger Guard, and a Trigger Guard Roll Pin. Exclusive to this builders kit are Seekins Precision Takedown Pins (2) for pivot and rear operations, two Takedown Pin Detents, two Takedown Pin Springs, a Set Screw Hex, and two SHCS Hex. This kit is intended for lower receiver assembly and includes the necessary hardware to complete a functional lower.