Specific Gravity is the ratio of the mass of a solid or liquid to be mass of an equal volume of distilled water. The standard temperature of calibration in the U.S. is 60°F / 60°F. All our Specific Gravity Hydrometers listed are calibrated at 60°F / 60°F.
Our ASTM Specification hydrometers are manufactured in strict accordance to specifications of ASTM (American Society for Testing and Materials) for accuracy and design.