Features: It is capable of detecting 4 kinds of gas: carbon monoxide(CO), hydrogen sulfide(H& 8322;S), oxygen(O& 8322;) and combustible gas(LEL). Pocket-size, light weight and ergonomics design make it convenient to carry and use. Backlight enables you to see the value clearly even in dark environment. 2 alarm methods: audio alarm and icons showed on the screen. Various functions meet your demand: gas monitoring, peak value display, low alarm setting mode, high alarm/TWA setting mode, etc. It is suitable to be used in petroleum, chemical industry, metallurgy, refining, etc. Specifications: Brand: SMART SENSOR Model: ST8990 Color: Yellow Material: ABS Carbon Monoxide Range: 0999ppm Hydrogen Sulfide Range: 0500ppm Oxygen Range: 030%VOL Combustible Gas Range: 0100-%LEL Operation Current: 220mA Short Circuit Current: ≤3A Operation Voltage: 3.7V Maximum Open Circuit Voltage: ≤4.2A Battery Capacity: 2500mAh Display Type: Segment type LCD Operation Humidity: 15%~95%RH Operation Temperature: 10& 8451;50& 8451; Storage Temperature: 040& 8451; Item Size: 11.45 * 6.44 * 4.45cm / 4.50 * 2.53 * 1.75in Item Weight: 200g / 7oz Package Size: 20 * 11 * 7cm / 7.87 * 4.33 * 2.75in Package Weight: 475g / 16.8oz Notes: -Gas monitor only, other accessories are not included. -Due to manual measurement, there may be deviation. -Due to photograph light or other reasons, the item in picture and material object may have slight difference, please in kind prevail. -Please read the manual carefully before you use it. Packing List: 1* Multi-Gas Meter 1* Manual 1* USB Cable