GAS VALVE, White Rodgers (An Emerson Brand) #37C73U-640 & is often cross-referenced & replaced with part #37C73U-173, Storage Tank Manual Water Heater Temperature Control Gas Valve. For Natural Gas Only, 4" WC, 30,000 - 70,000 BTU/hr., with 1-1/4" deep Brass Temperature Sensor Probe Insert Housing. This Gas Valve has been Cleaned & Bench Tested for proper function & temperature accuracy. This is a Pre-owned Gas Valve & is sold with a 90-day Warranty if Installed by a Licensed Plumber.