Greenlee 33A-1/2 Self Feeding Spade Bits, 6-1/4-Inch Length, 1/2-Inch Bore hardwood, softwood, plywood and drywall Forged and heat treated for long life For use in 1/4-Inch (6.4 mm) or larger power drills Hole in top center of bit for wire pulling Can be used with extensions for longer length