The Lochinvar & A.O. Smith 100093749-K Thermostat is an OEM replacement temperature-control component designed for compatible propane (LP) gas-fired water heaters. Featuring a 1.5-inch shank and 42.75K sensor specification, it monitors water temperature and regulates burner operation to maintain the desired temperature. This thermostat kit is used in compatible A.O. Smith and Lochinva... https://www.partshnc.com/100093749-lochinvar-ao-smith-k-tstat-15-shank-fg-4275k-lp