... B01IET7OC0?ie=UTF8&*Version*=1&*entries*=0Xi'an Hua Fan Instrument Co.,Ltd is one of the leading 12 ... welcome to buy or wholesale gas alarming detectors, CO detector, carbon monoxide detectors made in China from ... (O2), gas (EX), poisonous and harmful gases (CO, H2S, NH3, CL2, etc.)Response time: ≤30s(O2 ... );≤40s(CO);≤20s(EX);Time display: the machine is year, ...