CG-Q34-3 BW Technologies Calibration Gas Mixture Equivalent by GASCO Carbon Monoxide 100 PPM, Propane 50% LEL, Hydrogen Sulfide 25 PPM, Balance Air in a 34 Liter Cylinder 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