This is an economical device for controlling rH, with a 10–94% range with a 3–5% humidity differential. Dial in the desired humidity and the ESHS activates humidifiers to maintain the selected moisture level. (Note: this unit should be mounted with the sensor unit in your air system's recirculation duct in order to achieve maximum accuracy.) The ESHS becomes increasingly accurate at higher humidity. Rated at 7.2 amps. Ready to wire, with simple instructions included. Works with either 115 or 230V current. Should be used in conjunction with the Humidistat Relay (below) when used to operate devices with a startup amperage of more than 43.2 amps. For use in grow rooms and similar environments; not suitable for use in atmospheric sterilization chambers or other environments exceeding approximately 100 °F.