The CorePlus Diamond Tile Drill Bit provides professional, fast, clean cutting on porcelain and ceramic tiles. Leading-edge vacuum brazing technology ensures the diamonds stay bonded for an extremely long life. It uses premium-grade, braze-bonded diamonds designed to cut the hardest of materials. Easy start, no-drill guide required. Requires minimal water cooling, not a continuous water feed. Core waste material auto-ejects allowing continuous hole cutting. Fitted with a Tri-Flat shank for excellent performance on cordless drills.The CorePlus DTDM4PC Diamond Tile Drill Bit 4 Piece Set is supplied in a handy storage case. Contains the following sizes: 5mm, 6mm, 8mm and 10mm.