Product Description: The TriStar Viper Series Semi Automatic Gas Operated Shotguns are reliable, functional and hard working. Both wood and synthetic models have 3'' gas operated, semi-automatic shotguns that allow you to shoot light target loads to heavy waterfowl loads interchangeably. Removable choke system uses Beretta®/Benell® Mobil Threads, includes three choke tubes (IC, M, F), choke box, and wrench. Rubber Recoil pad, Fiber optic sight and shim kits standard.