API THERMO-HYDROMETERS

Description

Our API scale hydrometers measure the scale which was selected in 1921 by the American Petroleum Institute API , the U.S. Bureau of Mines, and the National Institute of Standards and Technology NIST as the standard hydrometer scale for petroleum products., The API scale is based on the following formula:API @ 60F = 141.5/ Specific Gravity @ 60F - 131.5, The thermometer scale where applicable for these thermo-hydrometers is located in the body. All instruments are suitable for certification for use as a primary reference with NIST traceability.