150MM Zinc Plate Jewelry Gem Polishing Flat Lap Wheel 6" Grinding Disc Lapping Polishing Disc Description: The new disc needs to be filled with water, rubbed from the edge of the disc with 80 grit sandpaper, and polished with 240 grit sandpaper, the zinc disc needs to be kept at a certain humidity and used with diamond grinding paste Specification: Name: Zinc Plate Jewelry Gem Polishing Flat Lap Wheel Diameter: 150MM (6") Aperture: 12.7MM Thickness: 10MM