CorePlus DCDKIT11 Diamond Dry Core Drill Bit Set, 11 Piece. The CorePlus Diamond Dry Core Drill Bit delivers a smooth drilling experience. Its 8mm diamond segments feature a high concentration of premium-grade diamond in the bond, utilising leading edge diamond/metal bonding, metallurgy, for long-lasting core life. A ribbed core body, and V-groove segments, enable the fast clearing of debris, allowing for a continuous fast cutting action, while the aerated core design enhances cooling, and extends core life. 1/2in BSP threaded Drill Bit is compatible with standard core drilling machines, and accessories. This 11 piece CorePlus Diamond Dry Core Drill Bit Set is supplied in a sturdy aluminium storage case. 5 x Diamond Dry Core Drill Bits: 38, 52, 65, 117 and 127mm.