54-9049E Biosystems Calibration Gas Mixture Equivalent by GASCO 50 PPM Carbon Monoxide, 25 PPM Hydrogen Sulfide, 1.62 % Methane,(32.4 % LEL),(50 % LEL Propane Equivalent), 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