The Lochinvar & A.O. Smith 100300201 1-Inch Gas Cock is a durable gas shutoff valve designed to control fuel flow in compatible heating equipment. It works by manually opening or closing the valve to regulate or stop the supply of natural gas to the burner, allowing safe equipment operation and convenient service access. Commonly used with Lochinvar and A.O. Smith boilers, water heate... https://www.partshnc.com/100300201-lochinvar-ao-smith-1--gas-cock