Airgas - X02HY60C3005533 - 40% Helium, Balance Hydrogen Certified Reference Material, Size 300 High Pressure Steel Cylinder, CGA 350

Certified Standards, sometimes referred to as working standards, are analyzed calibration mixtures used routinely in sience and industry. For the majority of applications, the tolerance of a Certified Standard is acceptable. These standards are generally prepared either by partial pressure or gravimetrically. Certification of the standard is performed through quality control analysis on instrumentation calibrated with Airgas Registered Laboratory Standards.