• Material: UV resistant plastic (prevents ageing caused by exposure to sunlight). • Nominal diameter 100 mm. • EC brushless motor of external rotor type with shaft turning in ball bearings, designed to guarantee notably low energy consumption and to provide 3 different air flow rates (the first two of which can be selected at the moment of installation). • The appliance is equipped with an electronic circuit board and relative humidity sensor, allowing it to switch automatically from a previously set minimum air flow rate to the maximum setting. The pcb incorporates an electronic timer able to automatically increase / decrease the airflow when product is wired to a light switch: when the light is switched on the product will pass automatically at maximum speed; when the light is switched off the product will return at minimum speed after a pre-set delay (the delay from 3 to 20 minutes can be selected during installation).