... underground Coal Mine, petrochemical, metallurgical, chemical, municipal gas, and other places at the scene detection; Technical ... 100~ 500)ppm: true value±5%; (500~1000ppm:true value±6%O2: ( 0.0~5.0 ) %vol: ±0. ... , lightContinuous working time>3 months ( without backlight)Sensor lifetime≥2 yearWorking current< 1mA ( without backlight ... to your requirement. Double gas detector 2 in 1 gas sensor equipment