* 5 in 1 MULTI-FUNCTION: The air quality monitor can accurately detect the level of CO2, TVOC, HCHO, Temperature and Humidity a high-precision infrared sensor and a built-in high-performance chip.It can detect the gas quality in living room, kitchen, office, car, school, hotel, campground and other environments * Real-Time Measurement: This CO2 meter can accurately capture the weak current generated during the electrochemical reaction to calculate the CO2 measurement result per second on the colorful display * Smart Alarm: Three different indicator levels demonstrate the air quality and the colour of the screen will change when the indicator level changes with an alarm.(NOTE:The alarm sound cannot be turned off.) * Built-in Battery: The Air Quality Monitor comes with a 1200mAh Built-in Battery. It takes 2.5 hours to charge the battery, lasts 6 to 8 hours when it is fully charged, and can be connected to power during use. * Easy to use: Once turn on the CO2 meter, it will automatically measure the surrounding air quality for you. Note: The measured results will be affected due to air changes constantly, please focus on long time measurements(over 60 minutes) to get a conclusion about the air quality of the overall environment.