Irwin Tools 1882793 SPEEDBOR Countersink Wood Drill Bit, 4-Piece

Tapered drill with widened flutes for drilling fast, clean pilot holes and ensures tight fit for screws, Adjustable four-cutter counter bore cuts and clears chips quicker for fast, smooth countersinking, Counter bore attaches to flats on shank with two hex screws for a secure fit and can be adjusted for controlled pilot hole depth, 1/4" quick-change shank reduces slipping in standard chucks and is compatible with all 1/4" quick-change chucks, including impact drills, Adjustable stop collar attaches to counter bore with two hex screws for a secure fit and can be adjusted for desired counter bore depth