Irwin Industrial Tools 43036 2-1/4-Inch Self Feed Bit For drilling large diameter holes in wood for pipe, conduit and other applications Replaceable coarse screw point drills quickly in dry, wet and gummy wood All bits have a 7/16-Inch hex quick change impact shank that fits 1/2-Inch or larger electric drills or 7/16-Inch hex impact wrench drills Precision milled shank eliminates run out and wobble Forged in one piece from high carbon steel for Maximum strength under tough drilling conditions