The VICTRA-20 Mount Assembly differs from other shotgun suppressor mounts. YHM's threads into the end of your shotgun's barrel using the standard choke threads to secure the suppressor to the shotgun, but it does not provide any choke or constriction to the shot load. That job is handled by our unique choke cone which is located in the front cap of the V-20 suppressor itself. Each mount is shotgun-manufacturer specific, and we offer a growing range of mounts that function with popular shotgun brands/models. The YHM V-20 Jam Nut (YHM-1250) is included with every mount. Length Added to Barrel: .950" Material: 17-4 Stainless Steel Finish: Melonite Gauge: 20 Made in the USA