Honeywell BW™ Quad Calibration Gas Mixture 2.5% CH4, 18% Oxygen, 25 PPM Hydrogen Sulfide, 100 PPM Carbon Monoxide Balance Nitrogen In 34 Liter Aluminum Cylinder for use in calibrating multi-gas fixed or portable detectors. Gas Component 1 Type % METHANE Gas Component 1 Amount 2.5 Gas Component 2 Type % OXYGEN Gas Component 2 Amount 18 Gas Component 3 Type PPM HYDROGEN SULFIDE Gas Component 3 Amount 25 Gas Component 4 Type PPM CARBON MONOXIDE Gas Component 4 Amount 100 Gas Component 5 Type % NITROGEN Gas Component 5 Amount 78.25