TVOC Sensor: The design of the co2 detector meter with TVOC sensor to monitor the CO2 value, temperature and humidity of the air to keep your health environment, we recommend you to use the USB charger Real-time monitoring and automatic alarm: The carbon dioxide monitor can detect the air in real time and with a CO2 concentration of 1999. Four warning lights flash at the same time for alarm Easy to read: Co2 sensor with intelligent color screen and clear numbers. Wide application: Portable CO2 monitor with compact design, suitable for monitoring air quality at home, schools, office buildings, hospitals, restaurants, shopping malls, factories, hotels, laboratories, etc. Why you need it: Perfect gift for your Valentine's Day gifts for him/her/kids, with the air quality monitor, you can definitely know what your environment is like and improve it according to the actual situation.