GASCO EB-314A Calibration Gas Mix, Carbon Monoxide 60 PPM, Methane 1.45% = (58% LEL) Pentane simulant, Oxygen 15%, 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