The Lochinvar & A.O. Smith 100093989 Natural Gas Final Burner Assembly is a replacement burner assembly designed for natural gas-fired water heaters. It includes essential components that regulate gas delivery and support pilot ignition and burner operation. By mixing natural gas with air and producing a controlled flame, it transfers heat to the water efficiently. https://www.partshnc.com/100093989-lochinvar-ao-smith-nat-final-burner-assy