3/8" (9.5) hole diameterBore hardwood, softwood, plywood and drywall. Innovative self-feeding design requires less effort and reduces vibration. Unique tapered design allows existing hole enlargement. 1/4" Quick change hex shank. Forged and heat treated for long life. For use in 1/4" (6.4 mm) or larger power drills. Hole in top center of bit for wire pulling. P.O.P. Packaged.