The UDP-9 Pistol is a compact AR-15 style firearm chambered in 9mm and fed with GLOCK(R) magazines. It features last round bolt hold open. Available in multiple colors. 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 6" 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 pistol grip Angstadt Arms 5.5" free float ultra light M-LOK hand guard Continuous top mil-spec 1913 picatinny rail Weight: Sub 5lbs Length: 22? Patent pending Accepts all Glock(R) aftermarket magazines. We recommend using factory Glock(R) magazines. Please see this page for magazine compatibility Includes one 15 or 17 round magazine