The Knightsbridge EX001T 100mm 4" Extractor Fan with Overrun Timer is a low noise, energy-efficient solution for improving air quality in bathrooms and kitchens. With a timer control function, this square-shaped fan runs for up to 30 minutes to effectively ventilate the space. The fan features a flat vent style, electric power source, and IPX2 rating for waterproofing. Made from durable polycarbonate material in a sleek white finish, this extractor fan can be easily mounted on walls or ceilings. With an operating sound rating of 35 dB and a voltage of 230V, this fan is an essential addition to any home for maintaining a healthy indoor environment.