GASCO Sulfur Hexafluoride Calibration Gas 50 PPM Balance Nitrogen in a 600 Liter Steel Disposable Cylinder CGA 580 SF6 Calibration Gas in Nitrogen contained in a 600 Liter Aluminum Disposable Cylinder, For Use with Any and All Gas Detectors, Cylinder connection CGA 600, Calibration Certificate NIST, Made in the USA