... .ISO9001:2008 3.Size:3,6,10,13,19,25,38,50mm Inert Ceramic Ball of Size 3,6,10,13,19,25,38,50mm ... Free volume (%)40Operation temp.(max) (°C)1100Moh’s hardness (scale)>6.5Acid resistance (%)>99.6Alkali resistance (%)>85 Size available & Crush strength ...