The Copeland Comfort Control (White-Rodgers) 3L05-1 Snap Disc Limit Control is an open-on-rise temperature safety switch rated 135°F to 175°F with a 40°F differential. It operates by automatically opening electrical contacts when surface temperature exceeds the set point and reclosing as temperatures drop. Commonly used in furnaces, air handlers, and unit heaters, it protects HVAC sys... https://www.partshnc.com/3l05-1-emerson-climate-white-rodgers-135175f-limitopenrise40fdif