This Yankee Hill Machine Nielsen Piston is designed for the Yankee Hill Nielsen Booster Assembly. The Yankee Hill Machine Nielsen Booster Assembly replaces the direct thread adapter on a YHM Sound suppressor or any other suppressor on the market which utilizes the 1-3/8"-24. They are designed to be used with handguns and barrels which require a Nielsen Piston spring. YHM's Nielsen Pistons are compatible with YHM's booster housing YHM-2055 as well as many popular pistol suppressors. They are constructed from heat treated 17-4 stainless steel for maximum durability and corrosion resistance. They feature 10 adjustment points to zero any impact shift. Available in a variety of thread patterns to fit most firearms. Note: Not compatible with Sidewinder suppressors