The Foxtrot Mike Products MIKE-9 AR9 Complete Billet Lower Receiver is made from billet aluminum with a black hardcoat anodized finish for added durability. It comes with a 6.5 oz. heavy buffer and a AR-10 .308 recoil spring for dependable performance. It comes equipped with a mil-spec 6-position buffer tube, and ambidextrous safety selector. Compatible with 9mm GLOCK-style magazines.Features: Billet aluminum Black hardcoat anodized finish 6.5 oz. heavy buffer AR-10 .308 recoil spring Mil-spec 6 position buffer tube Ambi safety selector A2 pistol grip 3D machined extra wide magwell Compatible with 9mm GLOCK-style magazines Billet magazine catch Steel ejector