The Yankee Hill Steel Thread Protector is designed to safeguard your rifle barrel threads when a muzzle device is not installed featuring 1/2X28 threading and a .730 outer diameter.Yankee Hill .22/5.56 Steel Thread Protector1/2X28 thread specification for secure fit.730 outer diameterDurable steel construction for long-lasting protectionPrevents thread damage during transport and storageEssential for maintaining your rifle barrel's threading integrity this thread protector ensures your muzzle threads remain pristine for future muzzle device installations.