Draeger 4597128 equivalent by GASCO 100 PPM Carbon Monoxide, 50% LEL Methane, 25 PPM H2S, 2.5% Carbon Dioxide, 17% Oxygen, 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, GASCO Calibration Gas is ISO 9001 Certified, Made in the USA