The Carlson's Choke Tubes® Tactical Muzzle Break Mobil Choke - Cylinder Bore is constructed from 17-4 heat-treated stainless steel and features cylinder constriction for use with all shot shells including lead, steel, hevi-shot, and even slugs. This choke boasts a porting design that helps to reduce felt recoil significantly for quicker follow-up shots. Lifetime warranty. Order now! Made in USA.