Bg 20ga inv plus choke tube cylinder FEATURES-20 gauge-Cylinder-Stainless steel with stainless finish-Longer choke taper inside Invector-Plus choke tubes for use with back-bored barrels-Produces excellent patterns with excellent uniform densities-All Browning tubes are set to industry constriction standards-Flush fit does not extend beyond end of barrel-Constructed of highly polished, 17-4 stainless steel for the ultimate in performance & durability