Unique Ball Nose End Diamond Finger Milling Bits Size 1-3/8" , a very useful tool for Enlarging and Shaping Holes in hard materials.
Heavily diamond coated, both sides and the end Compatible materials: Porcelain Tile Hard Ceramic Marble Stone Granite Counter Sink and More

Specifications:
Diameter: 1-3/8 inch (35mm)
Max hole dept: 50mm
Total Length: 65mm
Thread with 5/8-11 for most angle grinders;
Male 5/8-11 Thread to 3/8" (10mm) Hex Adapter for most electric drills (please turn off the hammer mode)

Because it is super easy to use and it does great job in enlarging, shaping, trimming holes in hard materials. You will get beautiful smooth perfect holes easily.
You will find this Diamond finger milling bit is very useful when you are doing the things below
1, replacing old faucets to standard one, because they require a larger hole,
2, tiling wall for bathroom and kitchen plumbing
3, cutting circles in tiles to fit the pipes

Tips of use：
Take your time, do not force the bit, you will get holes without chips, bumps or scratches.
Please help to cool the bit if you need to do several holes as high heat will melt the metal, then the diamonds will get off, then the bit gets dull.
Grinding will produce a lot of dust and noise, please use with goggles, ear plugs, vacuum and more
If your target material is expensive, do some test holes in scrap to get the feel for it before you do the job.