Calibration Gas Gas Name Carbon Monoxide Methane Oxygen Nitrogen Gas Mixture 250 PPM Carbon Monoxide 1.45 Percent Methane (29 Percent LEL) 17 Percent Oxygen Balance Nitrogen Background Gas Nitrogen Cylinder Capacity 66L Cylinder Material Aluminum Alloy For Use With Any and All OEM Gas Detectors Connection Size C-10 Max Pressure 1200 psi Cylinder Dia 2-9/10 In. Cylinder Height 10-1/2 In. Accuracy +/-5 Percent Calibration Certificate NIST