This CO2 measuring device is used especially to monitor the air quality in large rooms. These include meeting rooms, lounges and public spaces such as classrooms and kindergartens. Due to the large design of 388 x 288 x 43 mm, the CO2 indicator can also be read excellently from a larger distance. With the wall bracket for the CO2 indicator, the large display can also be mounted anywhere on walls. The built-in NDIR CO2 sensor for measurement has a measurement range of 9999 ppm. Apart from the high measuring range, the special feature of the built-in NDIR CO2 sensor in the CO2 measuring device is that the CO2 sensor does not require any maintenance. In addition, the CO2 meter also features a built-in temperature and humidity sensor to monitor climatic conditions. The CO2 meter also has a bar graph with which the measured CO2 content can be displayed graphically. The bar graph for the CO2 indicator is additionally divided into the colors green, yellow and red, which light up to fixed meas