Calibration Gas Gas Name Methane Nitrogen Oxygen Gas Mixture 3 Percent Methane/14 Percent Oxygen/Balance Nitrogen Background Gas Nitrogen Cylinder Capacity 103 L Cylinder Material Steel For Use With Any and All OEM Gas Detectors Connection Size C-10 (5/8 in UNF) Max Pressure 1 000 psi Cylinder Dia 3 21/64 in Cylinder Height 13 2/3 in Accuracy +/-5 Percent Calibration Certificate NIST