Description: Mainly used for drilling Porcelain Tile, Ceramic Tile, Marble, Granite ,Rebar Concrete and other hard material. Gold paints on the body of this bit to avoid getting rusty. Opening neat, smooth, no broken edges, no tremor phenomenon, chip Easily Small incision resistance,feature drilling stably, fast speed, not breaking the border. Suitable for drilling and mounting holes in stone counter tops, plumbing lines in showers, and vanities. Specification: Method of Use: Use Wet or Dry To prolong its using life, must use with water for cooling and lubrication. The can be used with Bench drill, hand electric drill. When you using hand electric drill, start slowly, 45 degree angle, go vertical after you make an initial mark. Material: Diamond Color: Gold 8mm: Overall Length: Approx.76mm/ 2.99inch Shank Diameter: Approx.6mm/ 0.24inch Opening Diameter: Approx. 8mm/ 0.31inch 10mm: Overall Length: Approx.80mm/ 3.15inch Shank Diameter: Approx.9mm/ 0.35inch Opening Diameter: Approx.10mm/ 0.39inch Package Includes: 1 Piece 8mm Drill Bit 1 Piece 10mm Drill Bit Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.