Benelli Crio M2/SBE II 20 Gauge Modified Flush Stainless Choke Tube. The specially-designed longer choke tubes of the Crio System allows for more gradual constriction of the shot charge which reduces pellet deformation. Frozen to -300 F Crio Chokes have a more evenly grained and slicker surface that provides less resistance to the shot charge as it passes down the bore. When coupled with a Crio Barrel the result is as much as 13.2% more pellets on target. Crio Chokes are the second part of the Benelli Crio System. Extra-long choke tubes with a more gradual constriction coupled with the slick surface created by the cryogenic treatment puts more pellets on target. The Benelli Crio System improves patterns by as much as 13.2% and yields denser more uniform shot patterns.