The alexander arms ar15 standard rifle upper was developed to function as the ideal item for anybody trying to find an exceptional option.With a black cerakote finish, and a m-lok handguard, you could get this upper to complete your build.Includes thread protector.Receiver Finish: Black CerakoteCaliber: 6.5 GrendelSights: None, Optic ReadyBarrel Length: 18"Twist: 1:8"Barrel Finish: BlackHandguards: M-LOKHandguard Finish: BlackBarrel Length Range: 18" to 18.99"