BW CG-Q34-5 equivalent by GASCO 100 PPM Carbon Monoxide, 2.2% Volume Methane, 25 PPM H2S, 18% Oxygen, Balance Nitrogen contained in a 34 Liter Disposable Aluminum Cylinder, For Use with Any and All Gas Detectors, Cylinder Connection C-10, Calibration Certificate NIST, Made in the USA