GASCO 602 Calibration Gas Mix, 1 % Carbon Monoxide, 1 % Carbon Dioxide, 1 % Methane, 1 % Ethane, 1 % Ethylene, 1 % Acetylene, Balance Nitrogen contained in a 34 Liter Aluminum cylinder With a C10 connection, For Use with Any and All Gas Detectors, Cylinder Connection C-10, Calibration Certificate NIST, Made in the USA