The UDP-9 Pistol is a compact AR-15 style firearm chambered in 9mm and fed with GLOCK magazines. It features last round bolt hold open.Features: Last round bolt hold open on an empty magazine Flared magwell for faster reloads Integrated oversized trigger guard 7075-T6 billet aluminum lower with a matte black hard-coat anodized finish 7075-T6 billet aluminum slick side upper receiver with appropriately sized ejection port and no forward assist or dust cover Threaded bolt catch screw 9mm bolt assembly for use with a standard AR-15 hammer 6" 9mm barrel in chrome moly with a 1/10 twist black melonite finish and A2 style flash suppressor Barrel is threaded 1/2A-36 and can accept a suppressor Magpul K2 pistol grip Angstadt Arms 5.5" free float M-LOK hand guard with a modern ergonomic 7 side design that allows for 45 degree offset mounting options Continuous top mil-spec 1913 picatinny rail Weight: Sub 5lbs Length: 22?