12 Gauge. 21" barrel length. SN: 21SA-KR480024. 3" chamber length. Modified Choke. Black Anodized receiver with black oxide finish to remaining parts set in black synthetic semi pistol grip stock with checkering to wrist and forend mounting rubber recoil pad. Gas-operated semi automatic shotgun fed by a tube magazine. Item features a dovetail cut receiver for optics mounting, front blade sight, and interchangeable chokes. Comes in original box with spare Cylinder and Full Chokes, and the owner's manual.