This thermostat is designed to replace Therm-O-Disc style 59T/66T thermostats on residential water heaters that use just a single element and thermostat. It has adjustable temperature settings, pre-set at 120 by the manufacturer. This item is CSA and UL Listed for the USA and Canada. Meets specification lengths for most American, AO Smith, Bradford White, Craftmaster, GE, GSW, Kenmore, Maytag, Reliance, Richmond, Rheem, Russ, Sears, State and Whirlpool brand water heaters.