Feature:【Including】Our High quality 5 PCS Countersink Drill Bit Set featuring M2 HSS Tapered pilot drill bits in sizes 1/8", 3/16", 5/32", 9/64", 11/64", 82° Countersink 3/8″ Counter-Bore sleeves, 82° Countersink 1/2" Counter-Bore sleeves and 1/4″ Hex Shank for a secure grip, universal compatibility (Size: 1/8" 9/64" 5/32" Drill+3/8″ 82° Counter-Bore, 11/64" 3/16" Drill+ 1/2" 82° Counter-Bore).【Quality Materials】The M2 HSS pilot drill has a helical chip edge to ensure fast cutting. The sharp tungsten carbide alloy cutting edge creates smooth countersinks and sink holes, ideal for machining screws that meet the 82-degree imperial (U.S.) standard.【Depth Adjustable】Drilling and countersinking depths are adjustable with hexagonal threaded screws and depth control stops, providing maximum versatility for a variety of applications.【Wide Application】Our countersink drills are widely applicable to natural wood, man-made boards, MDF, particle boards, plywood, aluminum, non-ferrous materials, decorative materials and so on.【Please Note】For best results and smooth edges, please operate countersinks at a slow speed of approximately 200 RPM.