Carlsons Cremator Choke Tubes feature our 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, less flyers and more dense patterns. 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. Made in the USA. *Note- Optima HP and Remington Pro Bore Long Range cannot be used with any steel shot larger than #2.