Feature: 1. Real Time Detecting and Comprehensive Detection: It provides readings of CO, O2 concentration, altitude, barometric pressure, temperature, and humidity so you can know the air quality around you in real time, whether indoors or outdoors. 2. High Precise Sensors and Long Lifespan: Equipped with electrochemical O2 and CO sensors that offer accurate measurements with a long service lifespan, providing dependable data over extended periods. 3. User Friendly Alerts and Visual Indicators: Features a 3 stage visual and audible warning system for CO concentrations, indicating 0-50 PPM levels with a green light, 51-200 PPM levels with a yellow light and alarm, and 201-500 PPM levels with a red light and continuous alarm. In addition, an audible alarm and flashing O2 indicate low or high O2 levels. 4. Powerful Battery and Efficient Charging: Powered by a 1500mAh rechargeable battery with fast Type C charging, capable of 72 hours of standby time, ensuring long lasting performance and quick recharging for continuous use. 5. Compact and Portable Design: This air quality tester is lightweight and portable, making it easy to carry and use in various settings, including homes, offices, and during openair activities like hiking and skiing. Specification: Name: Air Quality Tester Material: ABS Color: black Battery : 1 * built in 1500mAH battery (included) CO measurement ranges: 0-500PPM Resolution: 1PPM CO measurement accuracy: +10ppm or +5% 02 measurement ranges: 0-30% vol Resolution: 0.1% vol Atmospheric pressure measurement ranges: 300-1100hPa Relative accuracy: ±0.12hPa(950-1050hPa@25℃) Absolute accuracy: ±1hPa (950-1050hPa@0-40℃) Working temperature: 0℃-50℃ Working humidity: 0-95% (non-condensing) Input voltage: 5VDC, 2A Item size: 71 * 71 * 33mm / 2.80 * 2.80 * 1.30in Item weight: 220g / 7.76ounce . Package List: 1 * Air Quality Tester 1 * Charging Cable 1 * Lanyard 1 * User Manual