MSA 10048788 Calibration Gas Mixture Equivalent by GASCO 1.45% Methane (58% LEL Pentane Simulant), 20 PPM Hydrogen Sulfide 15% Oxygen, Balance Nitrogen, contained in a 58 Liter Disposable Aluminum Cylinder, For Use with Any and All Gas Detectors, Cylinder Connection C-10, Calibration Certificate NIST, Made in the USA