Features: 1. The tail of the dry hole opener is designed with a hexagonal shank, which is suitable for hand drills and bench drills. 2. Cooling wax is built-in with our diamond drill bits, which automatically dissipate heat while drilling and ensure stable performances for longer-lasting use. 3. The dry drill bit uses vacuum brazed technology, which allows them can be used at a higher temperature, high hardness, sharp and durable. 4. Perfectly suitable for cutting through hard materials such as granite, marble, masonry, concrete, tile, ceramic, and stone. 5. How To Use: Step 1: 45 lightly leaning on the porcelain drill, the smaller the force, the less likely it is to skid, maintain a high speed throughout the process, and open a crescents shaped positioning groove. Step 2: Put the electric drill upright slowly, while drilling, shaking at the same time can send out debris faster and improve the drilling speed. Specification: Material: 45 # Steel Color: Multicolor Size: 6.35 x 65.6 x 6mm, 6.35 x 65 x 8mm, 6.35 x 80 x 10mm, 6.35 x 80 x 12mm, 6.35 x 83mm Weight: 91g Package Included: 1 x Dry Hole Opener Kit