This is the ideal LPK for building out an AR patterned pistol caliber mil-spec dimension lower receiver. Includes everything but the trigger guard and magazine catch. Everything you need, nothing you don't. Kit Includes: Hammer Trigger Disconnect Bolt catch Bolt catch detent Selector Selector detent Fire control group pins (2) Takedown pin Pivot pin Pivot pin detents (2) Buffer retainer pin Complete spring kit A2 pistol grip assembly