Vent-trex fan
These are sometimes fitted in bathrooms and kitchens. The unit can be used in two ways, as an extractor fan or as a trickle vent.For ventilation, slide the button on the underneath of the unit to open to allow air in. To operate the fan, slide the button on the underneath of the unit and pull the cord, a light will come on. To change the fan speed, pull the cord twice quickly. Pull the cord once to turn the fan off and the light will go out.