1、TVOC Sensor: The CO2 detector with TVOC sensor is designed to monitor the CO2 value, temperature and humidity of air quality to maintain your healthy environment. It is strongly recommended to use USB for charging. 2、Real Time Monitor: The carbon dioxide monitor can detect the concentration of carbon dioxide in the air in real time, and four warning lights flash at the same time when it is above 1999. 3、Easy Reading: The CO2 monitor uses an intelligent color display with clear numbers. When the CO2 concentration is 1600-1999, the red warning light starts to flash and alarm. 4、Broad Utility: Portable carbon dioxide detector, compact design, suitable for air quality monitoring in homes, schools, office buildings, hospitals, restaurants, shopping malls, factories, hotels, laboratories and other places. 5、Ideal Present: The perfect gift for him or her. With the air quality monitor, you can definitely understand your environment and improve it according to the actual situation.