... grain, used for grinding and polishing mold, etc4. sponge grinding head:mainly used for grinding special internal surface and mold wall ... . Finishing polish and grind the high-classes glasses frame, such as nylon frame, stainless steel frame; suit for ... carving, jade carving, ceramic artwork,etc5.Felt bobs/wool grinding head: suit for mirror polishing various of mold, electronic, glass, ...