... 1.20 years professioanl manufacture 2.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 XINGFENG Catalyst ... hardness (scale)>6.5Acid resistance (%)>99.6Alkali resistance (%)>85 Size available & Crush strength SizeCrush strengthKg/particleKN/particle1/8''(3mm ... 122''(50mm)>5600>56 Inert Ceramic Ball of Size 3,6,10,13,19,25,38,50mm