GASCO 10L-414, Carbon Monoxide 300 PPM, Methane 1.45%Vol = (58% LEL) Pentane simulant, Hydrogen Sulfide 10 PPM, Oxygen 15%, Balance Nitrogen contained in a 10 Liter Aluminum Cylinder, For Use with Any and All Gas Detectors, Cylinder connection Built in Aerosal Trigger, Calibration Certificate NIST, Made in the USA