Description
The API Scale was selected as the standard hydrometer scale for petroleum products by the American Petroleum Institute (API), the U.S. Bureau of Mines, and the National Institute of Standards and Technology (NIST)
* The API Scale is based on the following formula: °API @ 60°F = (141.5/(Specific Gravity at 60°F) – 131.5
* The thermometer scale is located in the body of the hydrometer
* Calibrated for use at 15°C/60°F