1, 4 HSS drill bits for drilling holes with screw sizes #6, #8, #10 and #12 2, Specially designed steel sleeve countersinks or drill holes. Drill and countersink for wood screws without changing drill bits 3, Adjustable countersink sleeve depth with hex wrench. The standard 6.35mm hex shank is compatible with quick change 4, The drilling length can be adjusted for different screw lengths simply by loosening and tightening the set screw 5, Suitable for drilling workpieces with hardness below 25 HRC, such as carbon steel, sheet metal, insulation board, PVC board, wooden board, etc. Use on a drill with a chuck or connector