Quality Materials: High quality alloy blades, waterproof and anti-corrosion, hardened HSS steel blades sharper and more durable. Removable and Adjustable: Use the included hex key to remove the screw and adjust the length of the countersunk hole to adjust the drilling length of screws of different lengths. High Efficiency: Countersink Drill Bit Set Countersink Drill Bit with Depth Stop, with a centering drill, quickly discharge chips from the hole. It can effectively prevent the accumulation of debris and improve drilling efficiency. Good Design: Adjustable limits of the round shank for a wider range of applications, stable clamping effect and easy operation. Wide Usage: Woodworking countersink drill bit set is suitable for punching holes in wood, ideal puncher for solid wood, particle board, plywood, MDF.