Specifications: Made of high quality diamond material with fine workmanship, it is very durable, wear-resistant and easy to use. During processing, it has the advantages of no chipping, fast speed, sharpness and wear resistance. It is suitable for drilling stone, ceramics, vitrified tiles, glass, etc. Item Name: Hole Opener Material: Diamond Drill Bit Models: 50mm, 55mm, 60mm, 65mm, 70mm, 80mm, 85mm, 90mm Features: Fast Drilling Speed, Long-Lasting, Durable, Wear-Resistant, Easy to Use Size: 50mm/1.97", 55mm/2.17", 60mm/2.36", 65mm/2.56", 70mm/2.76", 80mm/3.15", 85mm/3.35", 90mm/3.54" (Approx.) Notes: First, it is positioned at a 45 inch bevel, and drills vertically, the speed should not be too fast, then the speed should be slowly operated at about 800-1000 rpm, and water must be added to cool the operation. 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. Package Includes: 1 x Hole Opener