... CT3 3. CE mark Explosion-proof PGAS-21 Sulfur Dioxide SO2 Gas Detector Intrinsically safe apparatus, Ex(ia) IIC T3Using ... -21Measuring gasToxic gas (O2, CO, CL2, NH3, HCL, HCN, SO2 & etc)Sampling methodDiffusionMeasuring principleElectrochemical cellMeasuring rangeRefer to ordering informationResponse time ... 100 Hydrogen sulfide 0-100 PPM 10 PPM PGAS-21-SO2-100 Carbon dioxide 0-100 PPM 2 PPM PGAS- ...