Calibration Gas Gas Name Pentane Oxygen Nitrogen Gas Mixture 0.35 Percent Pentane (25 Percent LEL) 12 Percent Oxygen Balance Nitrogen Background Gas Nitrogen Cylinder Capacity 221L Cylinder Material Steel For Use With Any and All OEM Gas Detectors Connection Size CGA 165 Max Pressure 250 psi Cylinder Dia 9 In. Cylinder Height 16-1/2 In. Accuracy +/-5 Percent Calibration Certificate NIST