58ES-428-20 Calibration Gas Carbon Monoxide 60 PPM, Methane 1.45% Volume = (58% LEL) Pentane simulant, Hydrogen Sulfide 20 PPM, Oxygen 15%,in Nitrogen contained in a 58 ecosmart Factory Refillable Aluminum Cylinder, For Use with Any and All Gas Detectors, Cylinder connection CGA C10, Calibration Certificate NIST, Made in the USA contained in a 58 ecosmart Factory Refillable Aluminum Cylinder, For Use with Any and All Gas Detectors, Cylinder connection CGA C10, Calibration Certificate NIST, Made in the USA