Portable CO Detector Carbon Monoxide Detector, Mobile CO Warner Carbon Monoxide Warning Detector, CO Meter with Temperature & Humidity DisplayThis CO detector is a 3 in 1 combined carbon monoxide, temperature and humidity meter. The compact and portable design makes this CO detector suitable for use not only at home, but also in cars, in motorhomes or when travelling. It can protect you from carbon monoxide poisoning anytime and anywhere. High Precision Carbon Monoxide Sensor This CO detector uses the principle of electrochemical reaction to quickly and accurately measure CO concentration. The built-in carbon monoxide sensor has a high measurement accuracy and a long service life. It is certified with the EN-50291 (EU standard for CO detectors) and offers high reliability. LCD Screen & Acoustic Alarm: All the readings are updated every two seconds and displayed on a high-resolution 3.7 inch LCD screen, which makes the CO concentration visible and easy to read. The CO alarm threshold can be adjusted according to the application scenario. If the CO concentration exceeds the set alarm threshold, this CO detector gives an acoustic alarm. Built-in rechargeable lithium battery: the built-in 2400 mAh lithium battery can hold this CO detector in standby mode approx. 100 hours of continuous operation. This CO detector can also work during charging and provide accurate readings. You can always leave it connected to a USB power supply to continuously monitor CO concentration if necessary. Standby mode: you can press the button to turn off the backlight of the screen and let this CO detector switch to standby mode for energy saving. In standby mode, the carbon monoxide sensor continues to work and continuously monitors the CO concentration. ATTENTION: This is a carbon monoxide (CO) detector, not a carbon dioxide (CO2) detector. If you turn on this detector in a normal living environment with clean air, it is normal that the carbon monoxide indicator is 0, as there is no carbon monoxide in clean air.