This is the catalytic combustion sensor for GMA200-MGSS, measuring gases & range: Ammonia 0 - 4% volume, Benzene 0 - 100% LEL, Butane 0 - 100% LEL, Butanone 0 - 100% LEL, n-Butyl alcohol 0 - 100% LEL, Carbon monoxide 0 - 100% LEL, Cyclohexene 0 - 100% LEL, Cyclopropene 0 - 100% LEL, Dimethyl ether 0 - 100% LEL, Ethane 0 - 100% LEL, Ethanol 0 - 100% LEL, Ethyl acetate 0 - 100% LEL, Ethylene 0 - 100% LEL, HC Mixture 0 - 100% LEL, Heptane 0 - 100% LEL, n-Hexane 0 - 100% LEL, 2-Hexanone MBX 0 - 100% LEL, Isopropyl alcohol 0 - 100% LEL, Methanol 0 - 100% LEL, Methyl acetate 0 - 100% LEL, 2-Methylpropan-l-ol 0 - 100% LEL, Nonane 0 - 100% LEL, iso-Octane 0 - 100% LEL, Pentane 0 - 100% LEL, Phenol 0 - 100% LEL, Propene 0 - 100% LEL, Toluene 0 - 100% LEL, Xylene 0 - 100% LEL.