[Face Icon Alarm]: The face icon of the CO2 Monitor is automatically switch when the CO2 at different level. [Green Face]400~1000ppm;[Yellow Face]1001~2000ppm;[Red Face]2001~5000ppm [Buzzer Alarm]: CO2 Detector is able to emit buzzer alarm when the CO2 level exceed the setting threshold(defalut is 1000ppm), you may manually set the alarm threshold by double click the power button [High Precision]The CO2 Meter is equipped with NDIR sensor, assure the accuracy measurement, it can measure carbon dioxide(400~5000ppm), temperature and humidity [LCD Screen ]Carbon Dioxide Detector is designed with colored and Large screen, make it very clear to monitor the air quality, help to keep the indoor air healthy [User-Friendly Design]The CO2 Monitor comes with Multi-Functions, Calibration, Bulit-in battery, USB cable and is compatible with any standard 5V DC power source<br><br>Please note: the physical slightly color difference or difference, does not affect the use, please do not mind, thank you! Material: plastic colour: As shown<br><br>Package Contents: 1 x CO2 detector 1 x data cable<br><br>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.