PROFESSIONAL TOOL: The O meter is a device that detects the presence of (O) gases in an area, often as part of a safety system. The professional detector adopts the electrochemical principle, which gives a quick and accurate measurement. POWERFUL FUNCTION: Sound and light dual-alarm when O gas concentration reaches the level of the alarm. With a lar LCD screen display the measured results, you can t gas concentration and temperature at a glance. RECHARABLE BATTERY: 3.7V recharable lithium battery, with micro USB interface, can be chard through the USB interface of the phone power adapter, computer, etc. Also you can use while charging. HANDHELD SIZE: The gas meter is compact and lightweight, professional designed to fit comfortable in your palm, easy to carry and operate. WIDELY APPLICABLE: The detectors can be used in car, metallurgy, power plant, chemical, mine, tunnel, underground pipelines and other places, effective prevention of hypoxia and poisoning., Manufacturer: SLZJWLPPA