Shaping Round Bevel Existing Holes for Tile Stone Porcelain Hard Ceramic Marble Granite Countertop.
You will find it is very useful when you are:
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 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. 
4.Application: Enlarge, shape and/or round bevel existing holes in Porcelain, Hard Ceramic, marble and granite

Specifications:
Diameter: 5/16 inch (8mm).
Max hole depth: 2 inch (50mm).
Total Length: 2.95 inch (75mm)
Thread: 5/8-11 for most angle grinders.
Color: black.
Note: Mgtgbao direct shop have Available Diamond Milling Bit diameter: Dia 8mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, you can choose what you need.

Packaging include:
1pc 5/16 inch (8mm) diamond finger drill bits.

Warming Tips for use：
①　Take your time, do not force the bit, you will get holes without chips, bumps or scratches.
②　If your target material is expensive, do some test holes in scrap to get the feel for it before you do the job.