Depending on the device version, the multi-sensor measuring device records the measured quantities CO2 (0-2000/3000/5000/10000 ppm), relative humidity (0-100% r.h.) and temperature (0 ..+50°C). The CO2 concentration is visualized via an LED traffic light (green/yellow/red). The version with a backlit LCD display shows the measured values and min/max values for CO2, relative humidity and temperature. In addition, the threshold values for the 3 LEDs of the traffic light function (CO2 concentration) can be set separately in the menu. The stand-alone device is operated with a plug-in power supply and can therefore be flexibly positioned in the room.As an option, the measuring device has a piezo buzzer and / or potential-free changeover contact. The alarm threshold can be set with a potentiometer. When this limit is exceeded, the buzzer beeps every 5 seconds or the changeover contact switches. The buzzer signal is deactivated for 10 minutes or permanently if necessary using a mute button.The CO2 concentration is measured using a non-dispersive infrared sensor (NDIR). The humidity and temperature are recorded by a digital sensor, which guarantees a highly accurate and long-term stable measurement result. The measuring device carries out an automatic calibration at regular intervals, which guarantees long-term stable measurements.The modern room housing has a quick-release fastener, extra-large ventilation slots, thermal decoupling and much more.The measuring device is set up using a high-quality table stand and is ideal for use at workplaces, schools, living rooms, medical facilities to reduce the risk of infection, e.g. To minimize COVID-19 with proper ventilation.