5-Piece Set: The set includes 5 high-speed steel (HSS) M2 tapered bits in sizes 1/8Inch, 9/64Inch, 5/32Inch drills+ 3/8Inch 82° counter-bore and 11/64Inch,3/16Inch drills+ 1/2Inch 82° counter bore and a 1/4Inch hex shank for both a secure grip and a universal compatibility with most drills. Depth Adjustable: Both pilot drill and counterbore depth are adjustable by adjusting the depth stop and drill bit with the wrench included, to achieve accurate drilling. The added plastics collar can reduce marring effectively. And Sturdy: The M2 HSS pilot drill bits with spiral chip flute, rapid cutting; steel alloy cutting edges create smooth countersink and counterbore holes, ideal for screws fitting 82-degree imperial (U.S.) standards. Widely Used: Working with natural woods, chipboard, man-made boards, plywood, MDF, decking,drywall,and various plastic boards. For best results and smooth edges, operate the countersink at slow speeds, approximately 200 RPM. Please note:the physical slightly