Carlsons Cremator Choke Tubes feature the brand new Triple Shot Technology (TST) and is offered in close mid and long range constrictions. TST is a series of three graduated rings in the taper section of the choke tube that allows a more gradual transition from the shotgun bore to the final constriction. This design offers reduced pellet deformation. These benefits make the Cremator Series effective on all types of waterfowl throughout the entire season. The Optima HP Cremator series has no size or speed restrictions with steel shot in the Close or Mid Range constrictions. The Long Range is limited to no steel shot larger than #2. 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.