BROWNING INVECTOR PLUS FLUSH MOUNT REPLACEMENT STAINLESS CHOKE TUBES Made from 17-4 heat treated stainless steel, these chokes are for shotguns using the Browning Invector Plus choke system. Steel, Lead, & Hevi-Shot may be used in all constrictions with the exceptions listed below.No Steel shot larger than #BB or speeds exceeding 1550 fps should be used in choke tubes tighter than full. No steel shot larger than #4 allowed in the Turkey constriction. These choke tubes are backed by Carlson's Lifetime Warranty and Made in the USA! Mfg: Carlsons