*High-precision Real-time Monitoring--The CO2 sensor has a built-in high-performance chip, and the NDIR sensor has high precision, stable performance and strong anti-interference ability. (Tips: Please let the device work short mins outdoor before use for most accurate results.) *Closeable Automatic Alarm Function--Then the CO2 concentration exceeds 1000ppm, an alarm will sound to remind people to pay attention to ventilation. If the user does not like the alarm clock, he can quickly press the main function key twice to turn on/off the automatic alarm clock function. *Easy to Identify and Read--With intelligent color screen display and clear numbers, the detector display is easy to identify and read. To keep the indoor temperature and humidity environment comfortable,monitor equipped with a temperature/humidity display and three measurement modes. *10 Hours+ Long Standby--The built-in 2000 mAh battery can provide more than 10 hours of standby time when fully charged, in addition to real-time power through the included usb charging cable, this enables long-term monitoring of air quality level. *Portable CO2 Detector--The CO2 concentration measuring instrument adopts compact design,small and light,convenient to carry. CO2 monitors are not only widely used in homes, but also in places where people tend to gather and poorly ventilated places. (For example: schools, hospitals, restaurants, shopping malls, etc.)