MSA 10058034 Equivalent by GASCO, 60 PPM Carbon Monoxide, 1.45% Methane, 10 PPM Nitrogen Dioxide, 15% O2, Balance Nitrogen contained in a 116 Liter Aluminum Cylinder, For Use with Any and All Gas Detectors, Cylinder connection C-10 5/8"-18 UNF, Calibration Certificate NIST, Made in the USA