Panasonic FV-WCCS1 WhisperControl Condensation Sensor, humidity control and countdown timer, ON/OFF condensation sensor 3-controls in 1-humidity control - automatically turns on exhaust fan to control humidity. Advanced sensor technology detects relative humidity and temperature for superior accuracy. Fan automatically turns off when the appropriate combination of temperature and humidity is reached, in all climate zones and for all seasons. Countdown timer manually turning the fan on initiates a 30 min countdown cycle. Manual ON/OFF control simply push the switch for manual fan operation and if you've turned your fan OFF before the room has been adequately cleared of moisture, the condensation sensor makes sure your exhaust fan clears the air. Additional benefits compatible with all single speed and/or single speed lite ventilation products Stylish decorator design with wall plate included LED Indicator light 1 year limited warranty ASHRAE ENERGY STAR Qualified LEED and CALGreen compliant Ground.