Self Loading Police Mark I 12 Gauge 3 Inch Chamber 22 Inch Cantilever Barrel Invector Choke System Adjustable Folding Rear Sight Synthetic Black Stock 8 Round. Aircraft grade aluminum alloy receiver. Barrel-mounted Weaver-pattern Cantilever rail. Hard-chromed bore and 3 inch chamber. Low/adjustable rear sight, red fiber-optic front sight. Standard Invector interchangeable choke tubes (Cylinder and Improved Cylinder included). Matte black synthetic stock with checkered gripping panels on forearm and grip. Premium non-slip recoil pad. Two steel sling swivel studs. Receiver-mounted bolt release. Curved operating handle. Crossbolt safety. Extended tube with aluminum cover. Eight 2.75 inch shells or 7 three inch shells.