Calibration Gas, CGA Number Not Applicable, Container Type Cylinder, Cylinder Capacity 58 L, Cylinder Diameter 3.53 in, Cylinder Height 14.25 in, For Use With All OEM Gas Detectors, Gas Mixture Methane (50 Percent LEL ) 2.5 Percent, Gas Type Methane, Product Type Calibration Gas, Chemical Formula CH4, CAS Number 74-82-8, Accuracy +/-5 Percent, Background Gas Air, Calibration Certificate NIST, Cylinder Material Aluminum Alloy, Outlet Connection Size 5/8 in, Outlet Connection Type UNF