Humidifier Controller, Switch Action Close on Fall, Opens on Rise, Switch Type SPST, Control Range 10 to 60 Percent RH, Humidity Differential 15 Percent to 40 Percent, Includes -, Overall Depth 2 3/8 in, Overall Height 3 3/4 in, Overall Width 5 1/4 in, Mounting Location Wall; Return Duct