Dynatech Regular Dry Diamond Core Drill Bits are ideal when drilling holes in brick and block. The tubes on the diamond bits are slotted to aid in both cooling of the core bit and removal of the cuttings. For years they have been the standard for dry core drilling. Dynatech also offers a starter bit assembly for easier hole starting. Regular dry diamond core drill bits are for use in brick and block walls only. When drilling concrete walls or floors, use our hand held wet cutting diamond core bit.