Methane (CH4) Calibration Gas -1971

Methane 0.0001% to 3.0% in Air
CO 0.0001% to 0.0999%, CH4 0.0001% to 2.5%, O2 2.0% to 23.5%, in N2
15% to 50% Methane, 10% to 40% Carbon Dioxide in Nitrogen