During operation of cooker hoods or extraction fans, smoke or exhaust from open fireplaces, closed fireplaces, and gas heaters can be drawn back into the room. This can lead to potentially fatal poisoning caused by the odourless and invisible gases carbon monoxide and carbon dioxide. For this reason, according to the furnace regulations (M-FeuVO para. 4), simultaneous operation of an air extractor and a flame source is only permitted if there is provision of an adequate supply of fresh air, e.g. from an open window. And our air extraction radio controller takes over this monitoring function for you. Because, only when the window is open, the built-in device for mounting in the extractor, or flush-mounted box, releases the voltage for the connected extractor. Advantage of this device is that the light function is maintained in the extractor, even if the window is closed.