1. Detect 4 kinds of gas: carbon monoxide(CO), hydrogen sulfide (H2S), oxygen(O2) and combustible gas(LEL). 2. Continuously monitor the CO, H2S, O2 and LEL gas concentration in the surrounding environment with professional and accurate measurement. 3. Sound & light vibration alarm works when one of the CO, H2S, O2 & LEL gas concentration reaches the level of the alarm. 4. Can set automatic shutdown time and concentration of alarm value. 5. Large color 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. Technical Details: 1. Carbon Monoxide(CO): 0-999pm;Resolution: 1ppm 2. Hydrogen Sulfide(H2S): 0-500ppm;Resolution: 1ppm 3. Oxygen(O2): 0-30%;0.1% 4. Combustible Gas(LEL): 0-100%;1% 5. Operation current: 230mA 6. Operation voltage: 3.7V 7. Battery type(include): BL-9C Rechargeable battery 8. Operation humidity: 15%-95% 9. Storage temperature: 0-40 10. Short circuit current: less than equal 3A 11. Maximum open circuit voltage: less than equal 4.2V 12. Display Type: Segment type LCD 13. Operation temperature: -10-50 14. Battery working runtime: 6 hours(no alarm) 15. Detection Gas: Carbon Monoxide(CO, Hydrogen Sulfide(H2S), Oxygen(O2), Combustible Gas(LEL) 16. time: Less than 20 Seconds 17. Dimension: 75x138x43mm Color:As shown Material:ABS Package Contents: 1 * Gas Detector Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.