#8 wood countersink, tapered drill, features widened flutes for drilling fast, clean pilot holes, 4 cutter, adjustable counter bore cuts & clears chips for fast, smooth countsinking, counter bore attaches securely to the flats on the shank with hex screws & adjusts for controlled pilot hole depth, 1/4" quick change shank reduces slipping in standard chucks, compatible with all 1/4" quick change chucks including impact drills, use for fine woodworking projects, bit diameter 11/64", counter bore size 3/8", plug size 3/8", shank size 1/4" g1.