Made from 17-4 heat treated stainless steel, these chokes are for MOSSBERG M835/M935 shotguns. 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!