The Soil Hydrometers meet ASTM E 100 “Specification for ASTM Hydrometers.” The S-300 is graduated to read specific gravity of the suspension. Model S-301 is graduated in grams per liter of the suspension. Made from molded seamless glass to ensure uniformity of volumetric displacement. They are used to determine particle size distribution of any particulate material that can be placed in a suspension that settles with time and has little particle density variation.
ASTM D 422, E 100