"Indent Item - Add 2-4 days to standard delivery time Flammable Gases Combustible gas/smoke: 100-10,000ppm Town gas: 300-5,000ppm Carbon monoxide + combustible gas Methane/Natural Gas: 500-10,000ppm Hydrogen: 50-10,000ppm Air Quality Control Oü (Ozone): 10ppb - 2ppm HýS (Hydrogen Sulphide) Freon (or other CFC's): 500-10,000ppm General air contaminant, including; NHü (Ammonia), NOý (Nitrous Oxide), Benzene, smoke etc. Sensitivity of individual gases varies. General air contaminants including; n-Hexane, Benzene, NHü (Ammonia), Alcohol, smoke, CO (Carbon Monoxide. Sensitivity to individual gases varies) CýHý (Acetylene): 500ppm 2000ppm NHü (Ammonia) "