Ranco humidity controls are designed to regulate the relative humidity of confined air spaces by cycling humidifying or dehumidifying equipment. J10 controls may be wall mounted and used to control exhaust fans or a furnace humidifier. The J10-808 control may also be duct mounted. The J10-809 Series can be wired in series or parallel with any 24 volt non-electric thermostat for humidity control in conditioned spaces.