During operation of cooker hoods or extraction fans, smoke or exhaust from open fireplaces, closed fireplaces, & gas heaters can be drawn back into the room. This can lead to potentially fatal poisoning caused by the odourless & invisible gases carbon monoxide & carbon dioxide. For this reason, according to the furnace regulations M-Fev VO§4, simultaneous operation of a fireplace & an air-suction plant is only permitted if there is provision of an adequate supply of fresh air, e.g. from an open window. & our extractor control takes over this monitoring function for you. Because the socket control device will only enable the voltage for the connected fume hood if the window is open. This device has been developed & certified in accordance with the requirements of the German Technical & Scientific Association for Gas & Water. The mechanical safeguard against plugging this device into other sockets prevents the impermissible operation of the device in mains sockets.