These benefits make the Cremator Series extremely effective on all types of waterfowl throughout the entire season. 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.