GASCO EB-429S Calibration Gas Mixture 200 PPM Carbon Monoxide, 75 PPM Hydrogen Sulfide, 2.5% Methane (50% LEL), 15% Oxygen, Balance Nitrogen contained in a ecobump aluminum cylinder, Material: Aluminum Alloy, Pressure: 1200 PSI, Dimensions: 4" x 2", Water Capacity: 0.066 Liters, Multiple Bumps: Approximately 250 bumps per cylinder, Free shipping No Haz-Mat, Certification NIST (ecobump regulator sold separately), Made in USA