This choke features Triple Shot Technology. TST is a series of three graduated rings in the parallel section of the choke, that allow a more gradual transition from the shotgun bore to the final constriction that conveys a host of benefits to the shooter, like reduced pellet deformation, a shortened shot string, and less flyers. There are also the benefits of an extended choke tube, including a 25 percent longer parallel section for tighter and more dense patterns, wrench less installation, quick removal, and muzzle protection. This choke is non-ported with a matte black finish. Like all Carlson''s tubes, the Cremator series carries a lifetime warranty, and are constructed out of premium 17-4 stainless steel.