Feature:1. Countersunk Drill: Suitable for countersunk drills, the countersunk bolts or screws are flush with the surface of the surrounding material or lower than the surface of the surrounding material when put in the hole2. Drill Hole Removal: These countersinks can be used to remove burrs left by drilling or tapping operations, thereby improving the finish and removing any dangerous pointed edges3. 3 Main Elements: Engineering drills has 3 main elements for making countersinks, pilot drill, countersink and countersink collar (sliding up and down)4. One Operation: Pilot holes, through holes and countersinks can be drilled in one operation, suitable for the most commonly used size screws5. With Collars: The collars on these twist drills allow you to change the depth of the pilot hole and the depth of the countersink6. Wide Application: Suitable for woodworking applications that require flat head screw head finishes, tapered drills have greater gripping power than standard drillsSpecification:Item Type: Tapered Countersink Bit Screw SetDrill Bit Material: High Speed SteelWooden Box Material: Solids WoodScrew specifications 5, 6, 7, 8, 9, 10, 12Size Drill Size(Approx.)Chamfer Size(Approx.)5 3.18mm or 1 or 8in9.5mm or 0.37in6 3.58mm or 9 or 64in9.5mm or 0.37in7 3.97mm or 5 or 32in9.5mm or 0.37in8 4.37mm or 11 or 64in9.5mm or 0.37in9 4.76mm or 3 or 16in9.5mm or 0.37in10 5.15mm or 13 or 64in12.5mm or 0.50in12 5.56mm or 7 or 32in12.5mm or 0.50in.Package List:7 x Drill Bit1 x Wrench1 x Wooden Box