Features: 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 hole 2.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 edges 3.3 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 screws 5.With Collars: The collars on these twist drills allow you to change the depth of the pilot hole and the depth of the countersink 6.Wide Application: Suitable for woodworking applications that require flat head screw head finishes, tapered drills have greater gripping power than standard drills Specification Item Type: Tapered Countersink Bit Screw Set Drill Bit Material: High Speed Steel Wooden Box Material: Solids Wood Screw specifications #5, #6, #7, #8, #9, #10, #12 Size  Drill Size(Approx.) Chamfer Size(Approx.) 5#  3.18mm / 1/8in 9.5mm / 0.37in 6#  3.58mm / 9/64in 9.5mm / 0.37in 7# 3.97mm / 5/32in 9.5mm / 0.37in 8# 4.37mm / 11/64in 9.5mm / 0.37in 9#  4.76mm / 3/16in 9.5mm / 0.37in 10#  5.15mm / 13/64in 12.5mm / 0.50in 12#  5.56mm / 7/32in 12.5mm / 0.50in Package List 7 x Drill Bit1 x Wrench1 x Wooden Box