The Angstadt Arms AR-9 Complete Upper Receiver is designed as a replacement or upgrade part for AR-9 rifles, SBRs, and pistols. It's compatible with Glock and Colt magazines and ensures smooth feeding and operation in sports and target shooting, home defense, or tactical applications. It features a 7075-T6 billet aluminum upper receiver with a side ejection port, an ultra-light skeletonized handguard with M-LOK mounting slots on the 3, 6, & 9 O’clock positions, QD swivel mounting points, a top mil-spec 1913 Picatinny rail, a chrome-moly steel barrel, a flash hider, a 9mm AR-15 bolt carrier group, and a mil-spec charging handle. It works with compatible AR-9 lowers and is ideal for upgrading your existing AR-9 build with a premium-quality upper for pro-grade performance.