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.