The countersunk heads have a titanium coating which makes them very strong. It bevels really clean, no jerking, and a very smooth and regular bevel, makes beautiful holes without bursting the plywood. for a clean and neat work and it will especially avoid accidents because it is easy to be injured with a screw that protrudes from it that it is badly inserted. This set of 6 reinforced and very hard cutters are perfect for all work at home. they hide the screws in the wood. es en HSS Hexagonal shank chamfering drill Lot of 6 cutters of different diameters which allow you to make chamfers on the edges of holes. Thus the head of your screw is well protected. These countersinks allow you to machine wood. Easy to use, to be fixed on the drill chuck. Attention: Not applicable to stainless steel, cast steel, iron, copper, aluminum coatings, and carbon steel, thin iron plates Material: hard steel