The original standard of excellence. 28 gauge Standard Invector flush fit choke tubes are available in constrictions ranging from Skeet to Full. They produce excellent patterns with uniform densities. All Browning Standard Invector choke tubes are set to industry constriction standards. Flush fit tubes do not extend beyond the end of the barrel. Constructed of highly polished, 17-4 stainless steel for the ultimate in performance and durability.