The maintenance-free microprocessor-controlled AERASGARD® RTM - CO2 is used to detect the CO2 content of the air in the range from 0...2000 ppm CO2. The actual temperature is detected at the same time. The measurement signals are converted into standard signals of 0 -10 V. The CO2 measuring transducer can be supplied with an optional switching output. Elegant enclosure made of plastic, with snap-on lid, based with 4-hole attachment, for installation on vertically or horizontally installed flush-mounted boxes, with predetermined breaking point for surface-mounted connection or in enclosure made of stainless steel (top and bottom parts are stainless steel, the cover is screwed on), vandal-proof version e.g. for schools, barracks and public buildings.