TriStar 24108 Viper G2 20 Gauge 26" 5+1 3" Black Rec/Barrel Black Fixed with SoftTouch Stock Right Hand (Full Size) Incudes 3 MobilChoke. 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 20 gauge G2 has a 26" barrel and black overall finish.