The KP-9 uses Glock magazines and accepts commonly available 9mm AR-15 blowback uppers. It is lighter weight compared to similarly configured receivers. The monolithic polymer receiver is made from injection molded 30% glass filled nylon. This unit includes a KE Arms RTS-1 Rekluse trigger and ambi selector.Features :Polymer receiver30% glass filled nylonLight weightAccepts Glock Magazines Includes 9mm Carbine Buffer and Spring Includes KE Arms RTS-1 Rekluse Trigger and Ambi Selector