... )Size:3-75mm 4)good quatlity with reasonable price Porous alumina Ball Product DescriptionHQ-MH Porous ceramic balls is also called ... from 25% to 95%,and every more 5% constitutes a grade, but 12 sizes by reference to the diameter, such as ... ,Φ20 ,Φ25 ,Φ30 ,Φ38 ,Φ50, Φ75. The products in other grade and sizes can be designed and manufactured if to the ...