This professional 4 in 1 gas detector is designed for detecting CO, HS, O and LEL gas. It can continuously monitor the CO, HS, O and LEL gas concentration in the surrounding environment, once the gas concentration reaches the level of the alarm, the alarm will sound, vibration and flash. High precision portable CO, HS, O and LEL gas tester with compact size and light weight, very easy to carry and operate. Features: Detect 4 kinds of gas: carbon monoxide(CO), hydrogen sulfide(HS), oxygen(O) and combustible gas(LEL). Continuously monitor the CO, HS, O and LEL gas concentration in the surrounding environment with professional and accurate measurement. Sound or vibration or flash triple alarms works when one of the CO, HS, O and LEL gas concentration reaches the level of the alarm. Large HD LCD display with backlight for easy reading. Can connect to a sampling pump to operate in closed place. Can be widely used in shipping, mining, oil exploitation, chemical, gas pipeline, tunnel construction, coal, metallurgy, paper, fire, municipal, textile and other industries. Specifications: Brand Name: SMART SENSOR Color: Blue Material: ABS Screen Size: 47 x 38mm or 1.9 x 1.5in Sensor: Electrochemical Principle Charging Port: Micro USB DC 5V Sampling Pump Power Supply: DC 3V power supply Operation Current: 230mA Short Circuit Current: 3A Operation Voltage: 3.7V Maximum Open Circuit Voltage: 4.2V Battery Type: BL-9C Display Type: Segment type LCD Operation Humidity: 15 percent -95 percent RH Operation Temperature: -10-50 Storage Temperature: 0-40 Battery Working Runtime: 6 hours (no alarm) Detection Gas: Carbon Monoxide(CO, Hydrogen Sulfide(HS), Oxygen(O), Combustible Gas(LEL) Measurement Range: CO: 0999ppm, HS: 0500ppm, O: 030 percent VOL, LEL: 0LEL Resolution: CO: 1ppm, HS: 1ppm, O: 0.1 percent VOL, LEL: 1 percent LEL Alarm Value Setting: Upper limit and lower limit alarm value can be set Alarm Alert: Sound or vibration or flash triple alarms TWA Alarm Value Setting: Time-weighted value, meaning the accumulated value measured within 8 hours STEL Alarm Value Setting: Short term exposure limit Item Size: 140 x 75 x 35mm or 5.51 x 2.95 x 1.37in Item Weight: 270g or 9.52oz Package Weight: 430g or 15.17oz Package Size: 24.5 x 9 x 6cm or 9.64 x 3.54 x 2.36in Package List: 1 x 4 in 1 Gas Detector 1 x USB Cable 2 x Screws 1 x Gas Calibration Hood 1 x Storage Bag 1 x User Manual (English)