HUB Fixed Mount Fixed mount insert engineered to expand suppressor compatibility across a wider range of firearms by providing a direct thread interface for HUB compatible suppressors with a 1.375-24 hub thread. Machined from 4140 heat-treated alloy steel for strength and durability and finished in QPQ black nitride for enhanced corrosion resistance. Length 0.765 inch and weight 1.84 oz. Available in a variety of barrel thread pitches to provide direct thread mounting for Nomad, Primal, Lazarus 6, Sandman X and other HUB compatible silencers.