"The TriStar Arms Viper Max Semi-Auto Shotgun is a 3-1/2"" gas-operated shotgun that allows you to shoot light and heavy loads thanks to its 2-piston system. Install the light pistol for 2-3/4"" target loads, or install the heavy piston for 3-1/2"" waterfowl loads. The secondary piston can easily be stored in the forearm for easy retrieval. The vent-rib barrel with matte sight plane and fiber-optic sight put you on target quickly while the overmolded rubber grips on the stock and forearm provide easy handling. Chrome-lined chamber and bore. New recoil pad and swivel studs. Compatible with Beretta/Benelli Mobil chokes, and includes 4 choke tubes (SK, IC, M, F). 5-round magazine with plug installed. Gas-operated Includes 2 pistons for light and heavy loads Secondary piston stores in forearm Vent-rib barrel with matte sight plane Fiber-optic front sight Chrome-lined chamber and bore Compatible with Beretta/Benelli Mobil chokes Includes 4 choke tubes (SK, IC, M, F)"