The Big Horn 18938 Quick Change Taper Drill Bit Set, made of the best quality steels and heat treated, is specifically designed to pre-drill for wood screws of various sizes and lengths. A four fluted countersink, designed to mount on a taper point drill, combines pre drilling for the screw threads, clearance drilling for the screw shank and counter sinking for the screw head all in one step. It can even do the counter bore for a wood plug if needed and a plug cutter, perfectly matched to the counter bore, comes with the set. The Kit includes a Quick Change Chuck, Countersinks, Counterbores, Taper Drills a Stop Collar and Plug Cutter. The kit is for wood screw sizes #5, #6, #7, #8 and #9. W. L. Fuller # 10393010C.