These weatherproof temperature controls have raintight enclosures that are rated NEMA 4X, so they're suitable for areas that are exposed to water spray, high humidity, airborne contaminants, and corrosive conditions. These controls are compatible with single-stage systems. Single-stage systems have a single output level and allow the system to be either on or off. These temperature controls have an air-coil sensor that monitors and regulates the ambient air temperature in heating and ventilation applications.