The Cremator series has no size or speed restrictions with steel shot in any of the three constrictions. You also get all the benefits of an extended choke tube including a 25% longer parallel section for tighter and more dense patterns wrench-less installation quick removal and helps with muzzle protection. They are offered in your choice of ported or non-ported configurations. Like all of our tubes Carlsons Cremator Series Choke Tubes are made in the U.S.A. carry a lifetime warranty and are precision-machined from heat-treated 17-4 stainless steel