Calibration Gas Gas Name Methane Nitrogen Gas Mixture 25 Percent Methane Balance Nitrogen Background Gas Nitrogen Cylinder Capacity 105L Cylinder Material Aluminum For Use With Any and All OEM Gas Detectors Connection Size C-10 Max Pressure 1200 psi Cylinder Dia 3-13/64 In. Cylinder Height 12-1/2 In. Accuracy +/-2 Percent Calibration Certificate NIST