Grinding Jars are premium High Alumina material or ceramic-based Roalox™. High-strength Roalox has four times the wear life of ordinary porcelain and reduces levels of silica contamination. Ultra-high fired High Alumina jars have higher service life, negligible silica contamination, and polyurethane coated body to minimize breakage. Both have wide mouths for fast loading/cleaning and neoprene gasketed lids with positive-locking bar and hand wheel. Jar capacities range from 0.1 to 6.6gal (0.3 to 25.0L), and diameters from 3.4 to 14.63in (86 to 372mm). Specimen capacity is approximately 25% of total jar volume, and Grinding Media should take up approximately 50% of total volume.