For the ventilation of medium-sized or large rooms in commercial applications, as well as bathrooms, showers, toilets, utilities and kitchens in domestic situations. The ‘intelligent’ timers turns the unit on appox. 40 seconds after activation, and continues to operate at the minimum speed for between 30 seconds and 30 minutes when switched off. Two speed motor, with double motor-fan housing, anti-vibration supports and backdraught shutter for silent operation.