Thermco’s Hydrometers are manufactured to the exacting specifications provided by NIST, ASTM/API and IRS and are calibrated against standards traceable to NIST Thermco’s offering of hydrometer include the numerous types such as Specific Gravity, Density, ATSM/API, Baume, Brix,Twaddle, % Alcohol, % Salts, etc. A certificate is provided with each hydrometer assuring that the user receives a quality instrument.