The Viper Max is a gas-operated, semi-automatic shotgun that allows you to shoot light target loads to heavy waterfowl loads utilizing a two-piston system. The secondary piston can be stored in the forearm for easy retrieval. It comes with 4 Beretta/Benelli Mobil Chokes (SK, IC, M, F) as well as over-molded rubber grips on the stock and forearm for added comfort.