【LCD color screen display】- The color screen display makes it easier for you to read and recognize in the dark.【CO2 Detector】- The color ring changes according to the current CO2 concentration.green 400-799ppm, yellow 800-1199ppm, orange 1200-1599ppm, red 1600-1999ppm, 2000ppm over four colors flash at the same time.【Function 3 in 1】- It can detect CO2 concentration, humidity and temperature in real time.CO2 detection range: 400-5000PPM.Temperature detection range: 0-50℃.Humidity detection range: 0-99%RH.【Rechargeable Battery】- 1200mAh large capacity battery for long working time, Type-C charging interface, easy charging.【Easy to carry】- The product is compact and easy to carry.The ventilation holes in the rear not only accelerate the convection between air and machine to achieve effective detection, but also provide a fine heat dissipation effect.