GASCO 103L-135A-1.135 1.135 % Methane (22.7 % LEL), Balance Air (20.9 % Oxygen balance Nitrogen) contained in a 103 Liter Steel cylinder With a C-10 connection Calibration Gas in a 103 Liter Disposable Steel Cylinder, Cylinder Connection C-10, Calibration Certificate NIST, Made in the USA