Features: his indoor air quality monitor accurately assesses intemperature & humidity level, and formaldehyde (HCHO), It is necessary to know the air quality where you live , can help you understand indoor air quality. Just presses power button, keep the device turned on and it will take the measurement automatically. The lithiums battery provide power, standbys time can last for 6hours (supplied with USB cable and charge). With its small size designs and a rechargeable battery, making comprehensive air quality monitor accessible. Benefits from the alarms system, including a buzzers and indicator bar for immediate pollution level warnings, complemented by convenient function. Equipped with a fast-responding and sensitive highs performances chip, the air quality monitor can precisely capture the weak current during electrochemical reactions. color & voice alerts keep you inform of current air quality conveniently. Specifications: Material:ABS Formaldehyde Dectection Range: 0~9.999mg TVOC Detection Range: 0~9.999mg Power Supply: 2pcs 1.5V AAABatteries (NOT included) Charging:Type C Size:Approx.59mm/2.32''x19mm/0.75'' Package Includes: 1x HCHO Tester note: Please allow 1mm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual color.