H-B DURAC Safety 19/31 Degree API Combined Form Thermo-Hydrometer (B61823-0200) Conforms to the accuracy requirements for ASTM thermo-hydrometers Combined-form; measures the relative density (specific gravity) of oil and petroleum related products in accordance with American Petroleum Institute (API) standards; Range: 19/31 degrees Built-in thermometer contains mercury-free blue spirit organic liquid fill; Range: 0/150 degrees F Individually serialized; lead free ballast and glass Packaged with a multi-language (English, French, German, Italian, Portuguese, and Spanish) Statement of Accuracy indicating accuracy traceable to NIST; Former HB Instrument # 4840