This model incorporates a condensation (humidity) sensor which automatically switches the fan on when the condensation level builds up. Once the condensation clears the fan turns off. It can also be connected to work with the room light switch. Requires at least a permanent unswitched live and neutral connection. If the timer functionality is required then an additional switched live connection is required. _Mains voltage 220/240V AC 50Hz. See product description for electrical connection requirements _Extraction rate 63 litres per second, 230 cubic metres per hour _Power consumption: 25 watts. Sound output 40dB(A) @ 3m _Spring operated backdraught shutter. Class II - double insulated. IP44 rated _Dimensions: 205mm wide x 205mm tall x 50mm deep (beyond installed surface). 150mm diameter spigot, extends for 60mm. For connection to 150mm / 6 inch ducting