This lower parts kit helps you to build a custom AR15 from the ground up. It features Mil-spec dimensions and coating ensure the highest quality and correct component interface. The kit includes Takedown/pivot Spring, Takedown/pivot detent, Trigger/hammer pin, Takedown pin, Pivot pin, Bolt Catch/spring, buffer, and roll pin, safety selector/spring and detent, buffer retainer and spring, trigger guard and roll pin, A2 pistol grip/screw and lock washer, hammer and disconnector spring, magazine catch body/spring and button, hammer, trigger, and a disconnector.