You can use core drills to cut holes in ceramics, tile and glass without chipping or cracking. Our diamond-coated core drills have a 3 mm 1/8" shank, medium-fine grit and are made of stainless steel on which the diamond particles have been electroplated. The 6 piece set is packaged in a reusable pouch. The set of 6 includes sizes 1.5, 2.0, 2.5, 3.0, 5.0 and 6.5 mm