Features : Indoor CO2 Monitor: Compact size Body with hollow back design for carring and . Big colorful LCD digital screen for people easy to identify and read. Not only monitoring the CO2 content, also can test the temperature & humidity Necessity of Air Quality Monitor: Carbon dioxide (CO2) is not harmful to human body when it is low, but when it overs a certain amount, it will affect the breathing of humans (and other organisms). If serious, life is threatening. Thus, we have to monitor the CO2 content of air for keeping health Advanced NDIR Technology: CO2 meter uses high precision NDIR sensor technology to detect carbon dioxide content accurately and quickly. and it can hazard assessment, when CO2 of air exceed the setting alarm value(alarm value: 1000 ), it will warn to remind people to open the window or turn on air purifier for keeping balance of air. Convenient for Carrying: CO2 Monitor built-in 1600mAh battery. It can be used continuously for about 8 hours after full charging.So 't worry, take the CO2 meter to anywhere you want go. Easy to Use: Each turn on, CO2 detector need to automatic calibration, so please put the air quality detector in a ventilated place, after 1-2 minutes calibrating, CO2 tester can be used normally Various Use: A air quality monitor is indispensable for a family. Help for detecting gas and air pollution in homes, kitchens, bedrooms, offices, schools, cars, hotels, travel, camping, parties, etc., to always protect you and your family under healthy air conditions Air Semiconductor Sensor: 4-in-1 air quality monitor adpots intelligent air semiconductor sensor to test the temperature and humidity value of air. Compare with the common sensor, it is more sensitive, accurately and stable; Built-in1600mAh battery Material: ABS colour: white Package Contents: 1 x Air Quality Monitor 1 x USB charging cable 1 x English instructions 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.