Made of lead-free ballast and glass, this 330mm (13") long plain form hydrometer measures the relative density (specific gravity) of oil- and petroleum-related products in accordance with the American Petroleum Institute (API) and the American Society of Testing Materials (ASTM) E100 standards. It is calibrated traceable to NIST standards at three points and is supplied with a detailed calibration report stating corrections to one-tenth of the smallest division. It is serialized and conforms to the accuracy requirements of ASTM hydrometers. The temperature standardization is 60°F/60°F. It is packaged in a recyclable, deluxe storage box. Note: ASTM calibrated hydrometers should be stored in a clean, dry, safe place. They should not be subjected to extreme temperatures.