This diamond polishing disc is made of material with diamond coating on one side, which has high hardness, wear resistance and excellent impact resistance, and good electroplated diamond particles provide a long service life [3 different diamond polishing discs]: There are 3 different diamond flat grinding discs, respectively #600#1000#300, to meet different grinding needs [WIDE APPLICATIONS]: This diamond grinding disc is specially designed for cutting or grinding and glass. Especially suitable for jewelry gem making, such as: polished crystal, , gemstone and jade, etc. [Dimensions]: This diamond grinding disc diameter x arbor hole: 8 inches x 1/2 inches, thickness: 1.5 mm, max. Working speed: 30000rpm Colour:Silver Material:diamond Size:Outer diameter:200mm Package Contents: 3 * Diamond Polishing Disc Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.