Features:Common Screen display -CO2 Technology: infrared (NDIR)Temperature unit ℃ or °F, 24 hours real time monitoring.Detection range: CO2 (400-5000 ppm)CO2 Alarm value: 800ppm-2000ppm ,but this value can be set by users. CO2 Alarm on /off functionPower supply:rechargeable Li-battery 1600mahColor: ..