The Sharps Bros lower parts kits contain all high quality, 100% USA produced components, manufactured to our exacting standards. Each kit is guaranteed to fit your mil-spec dimension lower receiver. We don’t use foreign made or polymer parts. These are quality kits at an excellent price. AR15 Lower Parts Kit – Builders Special (no fire control). Includes: Bolt catch, Bolt catch detent, Selector, Selector detent, Magazine catch assembly, Fire control group pins (2), Takedown pin, Pivot 9in, Pivot pin detents (2), Buffer retainer pin & Complete spring kit.