Indicates when it is time to ventilate ... Fresh air in closed rooms is important for concentration, for a good night's sleep and minimises the risk of infection via virus-laden aerosols. The measuring device monitors the CO2 concentration, room temperature and humidity indoors. The display illumination in traffic light colours shows at a glance whether the CO2 value is in the green range or whether there is a need for action. A history of average values is displayed for the last 24 hours. The display can be operated with alarm function, permanent or switched off illumination. Measuring range CO2: 0-9,999 ppm, temperature: 0-50°C, humidity: 1-95 %. Power supply via USB cable (mains adapter not included). Material: synthetic material, metal Measurements: 10.5 x 3.3 x 5.6 cm