CALGAZ calibration gas 15PPM Hydrogen Sulfide (H2S), 100PPM Carbon Monoxide (CO), 2% Carbon Dioxide (CO2), 2.5% (50% LEL) Methane (CH4), 18% Oxygen (O2) Balance Nitrogen 58 Liter Aluminum Cylinder, Inlet: C-10, Cylinder/Blend: 8AL 15PPM H2S/100PPM CO/2%CO2/2.5%CH4/18%O2/N2, Catalog: A0445627