Materials - These diamonds are made of high-speed steel drill bits that are durable and long lasting with sevice.Great fit - This diamond-coated Core drill removes a complete circle of glass, marble, ceramic, granite, ceramic or other. Like any standard bit, they are diamond coated for these purposes.Easy to use - This diamond drill has excellent quality and good performance, excellent cleanliness and precise holes.Colour: silverMaterial: metal alloySize: 6-32mmPackage Contents:10 * Diamond Drill BitsPrecautions - When using a diamond drill, use lubrication (water) or the diamond core Drill will burn.Only the above package content, other products are not included.Note: Light 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.