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 BerettaA(R)/BenellA(R) Mobil Threads includes three choke tubes (IC M F) choke box and wrench. Rubber Recoil pad Fiber optic sight and shim kits standard backed by a five-year warranty.