The Irwin Cordless Multi-Purpose Drill Bits have been designed for cordless low /min multi-purpose drilling. In tests they produced between 90-129% more holes per battery charge than leading competitors. They have a four-facet ground carbide tip for lower drilling pressure and better centring and allow for combined drilling into wood and brickwork: the Cordless Drillbit is excellent for such drilling jobs - where you drill through wood into brickwork. Only one drillbit is needed to do the job and will drill a wide selection of different materials like: Brickwork, Ceramic Tiles, Breeze Block, Wood, Dry Wall, Gypsum Board, Limestone, Slate, Marble, Eternite and Plastics/Reinforced plastics. Irwin Multi-Purpose Cordless Drill Bit Set 7 Piece Sizes: 4, 5, 6, 7, 8, 10 and 12mm.