[3-in-1 to Portability]The CO2 device is designed with a rack on the back to satisfy all your needs: indoor sleeping, travel, or . If you need to move the monitor around frequently, you may want to consider a portable or handheld CO2 monitor that is easy to carry. What's more, this device is easily portable and , making it perfect for use , in offices, classrooms, and other spaces. [Real Time Monitoring]A CO2 monitor equipped with an alarm will alert you when the value increases. The frequency of the alarm will increase (4 levels of alarms). If you need to turn off the alarm, you can press the "S" key. You can calibrate the CO2 monitor to its accuracy over time. [Rechargeable Battery & Adjustable Brightness ]With long-lasting battery life, you can use our CO2 monitor for extended periods without needing frequent battery changes. Charging the CO2 monitor for 5 hours ensures 18 hours of usage. You can also adjust the monitor's brightness to 3 different levels to protect your eyes when you are in different light. [High Precision & Sensitivity]Our CO2 monitor is designed with a highly accurate sensor that will measure the carbon dioxide levels and other airborne particles which may be harmful to you and your family. With a clear and easy-to-read display screen that shows the CO2 levels in 0-5000 , this monitor ensures you're breathing in healthy air. Note: Back with stand Material: ABS colour: white Package Contents: 1 x Portable CO2 Monitor Meter Sensor 1 x USB cable 1 x Lanyard 1 x English Manual 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 picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.