Calibration Gas, CGA Number Not Applicable, Container Type Cylinder, Cylinder Capacity 116 L, Cylinder Diameter 3.5 in, Cylinder Height 14.3 in, For Use With All OEM Gas Detectors, Gas Mixture Carbon Monoxide 250 ppm, Methane (50 Percent LEL) 2.5 Percent, Gas Type Carbon Monoxide, Methane, Nitrogen, Oxygen, Product Type Calibration Gas, Chemical Formula CH4, CO, N2, O2, CAS Number 630-08-0, 74-82-8, 7727-37-9, 7782-44-7, Accuracy +/-5 Percent, Background Gas Air, Calibration Certificate NIST