5 in 1 Function: Multifunction air quality monitor cares for and can be widely used , office, classroom, hotel, gym, greenhouse, warehouse, etc. Carbon Dioxide Tester: Adopts semiconductor sensor, air convection detection, quickly and accurately detects CO2 concentration in the living environment. LCD Color Screen: Displays CO2, CO2 , HCHO (formaldehyde), TVOC, temperature, humidity and battery level. LCD digital color screen for easy and clear reading even in dark environments. 4-color Indicator & Alarm Buzzer: 0-799PPM (Green), 800-1199PPM (Yellow), 1200-1599PPM (Orange), 1600PPM and above (Red). The buzzer alarms when the CO2 concentration is above 1500PPM. Rechargeable Design: Built-in 1200mAh rechargeable lithium battery for strong endurance. With type-C USB interface for quick charging via power adapter, power bank, laptop, etc. Colour:black :plastic Package Contents: 1 x Air Quality Monitor Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.