... 3. Comply with ROHS 4. For metal parts surface polishing Polishing stones are the indispensable additives for metal grinding and ... porcelain, high-frequency porcelain, resin, and metal, etc. The polishing stones (abrasives materials) are used at centrifugal grinders, vibratory grinders ... on the metals.The following is our products of polishing stones:MaterialShapeSize(mm) alumina porcelainballΦ2Φ3Φ4Φ6 ...