About this item MULTIFUNCTIONAL & PORTABLE This CO detector is a 3 in 1 combined carbon monoxide, temperature and humidity meter. The compact and portable design makes this CO detector very suitable for use in cars, motorhomes or travel. 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 2.45 inch LCD screen, which makes the CO concentration visible and easy to read. If the CO concentration exceeds 50ppm, this CO detector emits an acoustic alarm. Built-in rechargeable lithium battery: the built-in 1000 mAh lithium battery can hold this CO detector in standby mode approx. Keep working continuously for 70 hours. 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 After one minute of inactivity, this CO detector automatically turns off the backlight of the screen and goes into standby mode for energy saving. In standby mode, the CO 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. See more product details Product specifications: Model: HD09. Carbon monoxide measurement range: 0-999 ppm (5 ppm) Temperature measurement range: -10C to 50C (2%). Humidity measurement range: 0% to 95% RH (2% RH). Warm-up time: 35 seconds. Data refresh frequency: 2 seconds. Power supply: built-in 1000mAh lithium battery. Charging input: DC 5V/1A. Product size: 90 x 55 x 17 mm Item Package Weight:65g Box contents: HD09 x1; USB cable x1; user manual x1. CO concentration display. Depending on the carbon monoxide concentration, the device displays a coloured icon on the screen. Green: 0-50ppm, safe; Yellow: 51-100ppm, ventilation required; Orange:101-200ppm, ventilation required; Red: 201-999ppm, hazardous CO concentration alarm 51-100ppm: the alarm sounds 3 times every 3 minutes; 101-200ppm: the alarm sounds 5 times every 3 minutes; 201-999ppm: The alarm will sound continuously. You can press the S button to stop the alarm. Charging time and standby time. The built-in lithium battery can be used in approx. 4 hours and this CO detector in standby mode for approx. Keep working continuously for 70 hours. If no button is pressed, the device turns off the backlight of the screen after 30 seconds and goes into standby mode for energy saving. In standby mode, the gas sensor continues to work and continuously monitors the carbon monoxide concentration.