Draeger 4597069 Calibration Gas equivalent by GASCO 50% LEL Pentane, 17% Oxygen, 100 ppm Carbon Monoxide, 25 ppm Hydrogen Sulfide, Balance Nitrogen Contained in a 58L Liter Disposable Aluminum Cylinder, For Use with Any and All Gas Detectors, Cylinder Connection C-10, Calibration Certificate NIST, Made in the USA