Description: Made of high quality diamond material, durable and long service life. Internal waxing and cooling, dry drilling without water, high efficiency, multi-purpose drilling. When using a brazed diamond , the speed of the power tool should not be lower than 2000 rpm, the faster the speed, the better the effect. The cannot be pressed down hard, otherwise the will be easily damaged. Suitable for drilling most materials such as tiles, concrete, bricks, stone, glass, plastic and wood etc. Size: Drill Diameter 6/8mm: 6.5cm/2.56inch; Drill Diameter 10/12mm: 8cm/3.15inch Specification: Material:Diamond Size Chart: Drill diameter 6/8mm: 6.5cm/2.56inch Drill diameter 10/12mm: 8cm/3.15inch Package Includes: 1x Drill Bit(4 Pack) Note: 1. Please allow slightly error due to manual measurement. 2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. 3. Wish you a wonderful on-line shopping!