The detection and cotrol of CO, CO2 and C-H series gases are directly related with safety of humans. if incomplete combustion occurs in car engines, gas boilers, cooling and heating systems, or power generation systems, those gases can instantly become extremely dangerous, ELT supplies various types of gas sensors like CO, CO2, CH gases(CH4, C3H8, C4H10 etc) for the detection and measuring such harzardous gases at underground parking, parkades, tunnels, factories and underground arcades.