GASCO EB- 490-T Calibration Gas, Carbon Monoxide 200 PPM, Methane 50% LEL, Hydrogen Sulfide 40 PPM, Oxygen 10%, 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