The Yankee Hill Manufacturing Thread Protector is designed to safeguard your rifle barrel's threads when a muzzle device is not installed featuring 1/2X28 threading and .920 inch outer diameter.Yankee Hill .22/5.56 Thread Protector (YHM-3410-B)1/2X28 thread specification for compatibility.920 inch outer diameter steel constructionProtects muzzle threads from damage and debrisCompatible with .22 and 5.56 caliber riflesEssential for maintaining thread integrity during storage transport or when switching between different muzzle devices on your rifle.