Features: This air quality monitor with unique hexagon design, can be used in home & office. Wall-mounted CO2 Meter with LED large display, easy to watch in a distance. When the arbon dioxide concentration exceeds the standard, it will automatically remind of the alarm. Automatically detect OC2, pm2.5, temperature, humidity, with for time display. Detection range: PM2.5 (0-999 ug/M³), CO2 ( 400-5000 ppm). Can be used in homes, offices, schools, hotels, camping, parties, etc. Specifications: Material: ABS+Metal Size: 12x6.1cm/4.72x2.4in Installation: Wall-mounted CO2 Technology : infrared ( NDIR) PM2.5 Sensor technolology : La-ser Scattering Temperature unit between Celcius and Fahrenheit Switch 24 hours real for time monitoring. Detection range: PM2.5 (0-999 ug/M³) CO2 ( 400-5000 ppm) CO2 Alarm value : 1000ppm default ,but ,800ppm-2000ppm ,but this value can be set by users. CO2 Alarm on /off function Power supply：rechargable Li-battery 2000mah Package Includes: 1x Air Quality Monitor note: Please allow 1-3cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item.