Made in the u.S.A., carlons' cremator choke tubes features triple shot technology (tst).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.The choke tubes are precision-machined from heat-treated 17-4 stainless steel.Gauge: 20 GaugeConstriction Type: Mid-Range/Long-RangeConfiguration: Benelli Crio PlusFinish: BlackChokes Included: 2Material: 17-4 Stainless Steel