Biggest Gas Detecting Instruments Supplier in China, Most ... ISO9001: 2000 international quality system certification. (2)Colorimetric gas detector tube can detect the concentration of various gases ... detect different toxic gases in the air including CO,CO2,H2O,H2S,NH3,PH3,SO2,C4H10,CH3Br,C2H3CL, ... HCN,HCL,HF,NO,NO2over 600 types of target gas can be measured. For product Details, please contact ...