Calibration Gas, CGA Number CGA 291, Container Type Cylinder, Cylinder Capacity 552 L, Cylinder Diameter 4.5 in, Cylinder Height 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 Steel, Outlet Connection Size 3/4 in, Outlet Connection Type NGT, Standards ISO 9001:2015