The Lochinvar & A.O. Smith 100111304 Lower Thermostat with ECO WH9C is a replacement temperature control component designed for compatible electric water heaters. It works by monitoring water temperature in the lower section of the tank and regulating the lower heating element to maintain consistent hot water delivery. The integrated Energy Cut-Off (ECO) safety feature helps protect t... https://www.partshnc.com/100111304-lochinvar-ao-smith-lower-thermostat-weco-wh9c