Spike's Tactical set out to offer the best factory lower parts kit on the market! The lower parts kit they came up with exceeds military specifications by a long shot, they also have a much better fit, and finish! 100% made in the U.S.A. with a lifetime warranty. This kit does not include the fire control group. Kit includes: - Safety selector - Safety selector detent - Safety selector spring - Bolt catch - Bolt catch plunger - Bolt catch roll pin - Bolt catch spring - Magazine catch - Billet magazine catch button - Magazine catch spring - Pivot pin - Takedown pin