Feature: 1. Position at an oblique angle of 45 ° and drill in a vertical position (note that the speed cannot be too fast, and the speed should be slowly operated at about 800‑1000 rpm). 2. The hole opener can be used on bench drills, hand drills and drilling machines but not on impact drills. (Cannot be opened with impact function). 3. Suitable for all kinds of stone, ceramics, glass, glass, etc., keep adding water to cool down the holes. 4. The hole opener adopts a segmented designed, which has a small cutting resistance and is conducive to chip removal. 5. Universal triangular drill shank can effectively prevent skidding and bear more torsion. 6. Dedicated hole for chip removal, long oval designed is more conducive to chip discharge. Specification: Item Type: Hole Opener Optional Models: 90mm, 100mm Opener Model Total product length Handle length Handle diameter Working depth 90mm / 3.5in 80mm / 3.1in 5mm / 0.2in 9.4mm / 0.4in 54mm / 2.1in 100mm / 3.9in 80mm / 3.1in 5mm / 0.2in 9.4mm / 0.4in 54mm / 2.1in . Package List: 1 x Hole Opener