Calibration Gas, CGA Number Not Applicable, Container Type Cylinder, Cylinder Capacity 103 L, Cylinder Diameter 3.3 in, Cylinder Height 13.6 in, For Use With All OEM Gas Detectors, Gas Mixture Methane (50 Percent LEL) 2.5 Percent, Oxygen 18 Percent, Gas Type Methane, Oxygen, Product Type Calibration Gas, Chemical Formula CH4, O2, CAS Number 74-82-8, 7782-44-7, Accuracy +/-5 Percent, Background Gas Nitrogen, Calibration Certificate NIST, Cylinder Material Steel, Outlet Connection Size 5/8 In.-18