The DEWALT Extreme Impact Masonry Drill Bits have a carbide tip for fast drilling, with an innovative flute design for fast material removal. They have a 1/4in hex shank for use with impact drivers and screwdrivers with bit holder or chuck. Suitable for wood, plastics, concrete, brick, multi-layer materials and masonry. Ideal for engineers in construction, joinery and maintece applications Sizes 4, 5, 5.5, 6 and 8mm.