Higher raised shelf at the rear of the upper receiver to block gas from the shooters face Innovative keyway cut to prevent gas from flowing over the rear shelf Internal baffling inside the stem to create turbulence and slow down gas expansion Ported back pressure hole and relief cuts on the top and bottom to redirect the gas away from the shooters face Constructed out of 7075-T6 aerospace grade aluminum Finish : Flat Dark Earth Style : Short Hand : Ambidextrous Make : AR-15