Calibration Gas Gas Name Carbon Monoxide Methane Gas Mixture 100 ppm CO 2.5 Percent CH4 (50 Percent LEL) Background Gas Air Cylinder Capacity 21 L Cylinder Material Steel For Use With Mfr No 909-00000-B 909-00000-E 910-00100-B 910-00100-E 880-00032 880-00