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. 5-Piece Set: The set includes 5pc tapered bits in sizes 1/8inch,9/64inch,5/32 inch, 11/64inch ,3/16inchdrills+ 1/2inch counter bore and a 1/4inch hex shank for both a secure grip and a universal compatibility with most drills. And Sturdy: The M2 HSS pilot drill bits with spiral chip flute, rapid cutting; steel alloy cutting edges create smooth countersink and counterbore holes. 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., Manufacturer: Ounfhtrttk