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.