High AccuracyThe CO2 Monitor/Carbon Dioxide Detector adopts advanced NDIR sensor which enables fast, accurate and continuous monitoring of CO2 concentration (carbon dioxide concentration), temperature and humidity. Visual AlarmsEasily detectable CO2 indicator light (green, yellow, red) for real-time assessment of CO2 concentration. Audible Alarm detector of CO2 triggers the DIDI alarm at a concentration of 1000-5000 PPM; of course, you can also mute the sound temporarily or permanently, depending on your preference. Auto CalibrationIn operation, the CO2 monitor is automatically calibrated according to the concentration of the surrounding air . If necessary, you can also calibrate it manually. Where To UseHouses/apartments, bedrooms, cars, offices/meeting rooms, schools, hospitals, vegetable sheds, warehouses, etc.< /p>