GASCO 34L-314S-NO2: 60 PPM Carbon Monoxide, 50% lel Methane 2.5% by volume, 10 PPM Nitrogen Dioxide, 15% 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