The xpelair simply silent c4hts is a two speed extractor fan with a sleek smooth finish it is suitable for a wide range of applications including bathrooms shower rooms and toilets including zone 1 and 2 installations the fan meets buildings regulations part f and has a timer humidistat control which means that when connected to a remote switch such as a lighting circuit the fan will turn on when the circuit is switched on and overrun for a selectable time of 30s to 30 minutes when the circuit i