Yankee Hill Machine 1.375-24 HUB Direct Thread Mount Purpose-built to convert HUB compatible suppressors with a 1.375-24 hub into a direct thread mounting system. Machined from 17-4PH heat-treated stainless steel for high strength and wear resistance and finished in black oxide for corrosion protection, this direct thread mount provides a through-bore sized for .45 cal to maintain an unobstructed bullet path. The mount weighs 1.7 oz and is offered in a variety of barrel thread pitches to suit different firearm platforms. Installation begins by removing the existing mount mechanism from the suppressor, threading the HUB direct thread mount onto the suppressor using a 3/4 inch open-end wrench, and then threading the suppressor directly onto the barrel for a secure, repeatable connection. Made in USA.