Calibration Gas Gas Name Isobutane Nitrogen Gas Mixture 10 Percent Isobutane Balance Nitrogen Background Gas Nitrogen Cylinder Capacity 103L Cylinder Material Steel For Use With Any and All OEM Gas Detectors Connection Size C-10 (5/8 in UNF) Max Pressure 1000 psi Cylinder Dia 3-21/64 In. Cylinder Height 13-2/3 In. Accuracy +/-5 Percent Calibration Certificate NIST