About this item MULTIFUNCTIONAL AIR QUALITY MONITOR This is a 4 in 1 multi function indoor air quality meter. It can accurately measure carbon monoxide and carbon dioxide concentration, temperature and humidity at the same time. You can conveniently use it to monitor indoor air quality at home, office or car. Wide range of uses: this device can be used as a carbon monoxide or carbon dioxide detector. It is powered by a built-in lithium battery and is also suitable for mobile use, e.g. in the car, caravan, travel, tent camping, etc. It can monitor indoor air quality and protect you from carbon monoxide poisoning anytime and anywhere. High precision sensors: this device can quickly and accurately measure CO and CO2 concentration. The built-in electrochemical carbon monoxide sensor and NDIR carbon dioxide sensor have high measurement accuracy and a long service life. The CO sensor is certified according to EN-50291 (EU standard for carbon monoxide 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 readings visible and easy to read. The CO and CO2 alarm threshold can be adjusted according to the application scenario. If the CO or CO2 concentration exceeds the set alarm threshold, this device gives an acoustic alarm. Built-in rechargeable lithium battery: the built-in 2400 mAh lithium battery can hold this device in standby mode approx. 100 hours of continuous operation. This device can also work while charging and provide accurate readings. You can always leave it connected to a USB power supply to continuously monitor the CO and CO2 concentration when needed. ATTENTION: If you turn on this device in a normal living environment with clean air, it is normal that the carbon monoxide indicator is 0, as there is no carbon monoxide (CO) in clean air. See more product details Product specifications: Model: PTH-9E. Carbon monoxide measurement range: 0-500 ppm (5 ppm) Carbon monoxide alarm range: 150-500ppm (preset) Carbon dioxide measurement range: 400-5000 ppm (5 ppm) Carbon dioxide alarm range: 1500-5000ppm (preset) Temperature measurement range: -10C to 50C (5%). Humidity measurement range: 20% to 80% RH (2% RH). Data refresh frequency: 2 seconds. Power supply: built-in 2400mAh lithium battery. Charging input: DC 5V/1A. Product size: 98 x 90 x 40 mm Item Package Weight:200g Box contents: PTH-9E x1; USB cable x1; user manual x1. CO concentration display. Depending on the carbon monoxide concentration, the device flashes a coloured icon on the screen. Green: 0-99ppm; Yellow: 100-149ppm; Red: 150-500ppm; CO concentration alarm If the CO concentration is above the set alarm threshold, the detector gives an acoustic alarm. You can press the button to stop the alarm. Charging time and standby time. The built-in 2400 mAh lithium battery can be used in approx. 4 hours fully charged and lasts up to approx. 100 hours. You can press the button to turn off the backlight of the screen and let the device go to standby mode for energy saving. In standby mode, the gas sensor continues to work and continuously monitors the carbon monoxide concentration.