Dynatech vacuum dry drill bits are an inexpensive and fast way to drill holes in brick, block, and some concrete. Perfect for situations where water cannot be used or when dust control is a factor. Simply screw the vacuum swivel on your grinder or 1/2" drill, connect your vacuum hose from any vacuum source (shop vac, wet/dry vac etc.) and you are ready to drill. The vacuum suction pulls air down the outside of the bit and across the diamond segments. This aids in cooling, and removes cuttings quickly so that the new cuttings can be created. Fast removal of cuttings eliminates bit binding, provides faster cutting and produces longer bit life. For hard concrete or concrete with steel reinforcing (Rebar) use Dynatech Wet Cutting Core Bits.