RISE ARMAMENT PREMIUM LOWER RECEIVER PARTS KIT FOR AR-15 The Rise Armament AR-15 Customizable Lower Receiver Parts Kit provides most of the mil-spec parts generally used in an AR-15 build, while still allowing the flexibility to add common aftermarket upgrades, such as a pistol grip and match grade trigger components. Customizable lower parts kits offer an economical way to get all the small pieces needed for an AR-15 lower, without wasting money on the parts you won't use! KIT INCLUDES: Safety detent pin Safety detent spring Mag catch Mag catch spring Mag release button Bolt catch, Bolt catch spring Bolt catch Mfg: Rise Armament