... introduction:Portable H2S gas detector with 4-digit LED indication, adopting catalytic gas sensor and MCU, is intrinsically safe gas detector for mining industry. ... gas like H2S, CO, CH4 gas etcAlarm indicationSound, light, and vibrating alarmResponse time<30sDetector range1-100ppm (customized)Min reading1ppm (customized)Detection ... to avoid wrong operation- Intrinsically safe H2S Portable Gas Detector