Health protection through fresh air. Whether in a production hall, an open-plan office, or a school: the more people present in a room, the faster the air gets depleted. The result: the CO2 levels rise, and the concentration of everyone present decreases. But that's not all: as the amount of exhaled air increases, so does the burden of viruses and bacteria, which raises the risk of infection from airborne pathogens. Is it time to ventilate? The simple remedy is to open the windows and ventilate regularly. The Voltcraft CO-300 traffic light indicates when it's time to open the windows: it visually and audibly alarms when the carbon dioxide concentration in the room is too high. This allows for immediate action to be taken to minimize health risks in the simplest way possible—with fresh air from outside. Special feature: wall-mounted.