TriStar Viper G2 Pro Sporting 12 Gauge 3" 5+1 30" Vent Rib Barrel, Red Anodized Receiver, Black SoftTouch Stock, Fiber Optic Sight, 4 Extended Mobil Choke Included. The TriStar Viper series is a semi-automatic, gas operated shotgun that is reliable, functional and hard working. Its removable choke system uses Beretta/Benelli Mobil threads, includes three choke tubes (IC, M, F), choke box, and wrench. The Viper also features manual E-Z load mag cut-off, vent ribbed barrel with matted sight plane & fiber optic front sight and chrome-plated chamber. A shot plug is included. This 12 gauge G2 Sporting model allows you to shoot light target loads to heavy pheasant loads. Included is an additional SK choke.