These plain form hydrometers are available in a variety of models measuring specific gravity / relative density g/cm of liquids lighter and heavier than water in various ranges from 0.690 to 3.000. commonly used in industries such as food and beverage, chemical, pharmacology, transportation, refrigeration and more lead free ballast and glass individually serialized temperature standardization: 60°f 15°c hand inspected by our u.s. Quality team packaged with a multi-language english, french, german, italian, portuguese, and spanish statement of accuracy indicating accuracy traceable to nist note : hydrometers should be stored in a clean, dry, safe place, and should not be subjected to extreme temperatures.