Helix Hellion dry core diamond bits grind through porcelain tile like a hot knife through butter. No water needed...ever. Extremely long lasting and designed to be used at high speeds on an angle grinder. The connection is a 5/8"-11 female thread. Hellion Dry Core Bits are designed for ultra-fast, dependable coring of all UCS, Porcelain, and ceramic materials.  Hellion bits feature unique H cooling ports and internal/external diamond brazing on the barrel.  This helps the Hellion core the hardest porcelain without glazing or breaking. The connection is a 5/8"-11 female thread.