Angstadt Arms UDP-9 9mm Rifle Last round bolt hold open on an empty magazine Flared magwell for faster reloads Integrated, oversized trigger guard 7075-T6 billet aluminum lower with your choice of a matte black hard-coat anodized finish, Magpul Flat Dark Earth Cerakote or Tactical Grey Cerakote 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 Fire control group: Milspec AR-15/M4 Fire control group. The UDP-9(R) is compatible with most aftermarket 9mm PCC triggers. Please see this page for trigger compatibility 16" 9mm barrel in chrome moly with a 1/10 twist, black melonite finish and A2 style flash suppressor Barrel is threaded 1/2x28 and can accept a suppressor B5 Systems Bravo rifle stock and B5 Systems pistol grip 15" ultralight handguard with M-LOK(R) mounting interface on the 3, 6, 9 & 12 O'clock positions Weight: 6 lbs Length: 32? Patent pending Accepts all Glock(R) aftermarket magazines. Please see this page for magazine compatibility Includes one 15 or 17 round magazine