The high-definition LED screen enables you to read data and more easily. There are 4 different color on the screen indicating CO2 concentration levels: green for healthy, yellow for attention, orange for ventilation and red for danger. This allows for a quick identification of the surrounding air . use, put the CO2 sensor in the vent for 5-10 minutes for data calibration, if the air changes, please wait 35 seconds for the detector to sense the changeUsing NDIR non-scattering infrared sensor, CO2 detector has stable performance and high precisionCarbon dioxide detector real-time monitoring: real-time detection of indoor environmental , measured by three key indicators - carbon dioxide, temperature and humidity, comprehensive indoor air , to breathing healthWith a simple and generous design, mini size makes it easy to carry out, and a built-in 1000 mAh rechargeable battery can continuously work for 8 hours, allowing you to check the air anytime and anywhere. This portable CO2 monitor supports USB charging and has a low battery indicator.This mini carbon dioxide monitor is used for grow room, travel, camping, , , hotels, parties, wine cellars, kitchens, bedrooms, offices, schools, agricultural planting, indoor gardens, etc.Type:CO2 DetectorType:Carbon Dioxide Concentration DetectorColour:blackMaterial:ABSSize:73 x 73 x 18mmPackage Contents:1X CO2 Detector1X USb Cable1X English manualOnly the above package content, other 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.