The tacfire ar-15 parts kit contains one of each- a2 pistol grip, pistol grip screw, pistol grip lock washer, trigger, trigger pin, trigger spring, flat trigger guard, hammer, hammer spring, hammer pin, bolt catch roll pin, bolt catch spring, detent spring, bolt catch plunger, take down detent, bolt catch, magazine catch spring, magazine catch button, magazine catch, front pivot pin, detent selector, take down pin, buffer retainer pin, buffer retainer spring, disconnector spring, disconnector, selector and selector spring.Type: Lower Parts KitGun Model: AR-15 Parts KitGun Type: AR PlatformCaliber: .223/5.56