Choke Tube System: Benelli Crio; Shotgun Model: Benelli SBE II, SBE III, M2, Beretta 391A Extrema; Gauge: 12 Gauge; Diameter: 0.685"; Built to handle lead, bismuth, and steel shot; Capable of shooting any load with a flight-controlled wad; Produces a shorter shot stream for better knockdown power; Black nitride finish provides additional lubrication and protects against corrosion