ZDD Compatible with - 2-5mm, 5-10mm, 10-15mm, 15-20mm 90 Degree - Advantage of wear-resistant and durable, high chamfer concentricity, beautiful chamfering, etc HSS 4241 - High hardness and wear resistance, high cutting speed, sharp cutting edges. For material with hardness below 65HRC Angle Design - Rust and corrosion resistance. With the edge strength and sharpness, the use of large core diameter, tool rigidity, countersink cutting and cutting ability has been increased For all common drills - Drills from Hilti, Bosch, Makita, Hitachi, Fein, AEG, Metabo, DeWalt, Black ; Decker, Brder Mannesmann, Kress, Wolfcraft, Einhell, Milwaukee, Flex etc. (use protective oil to prevent rust.) 90-degree design 4-piece countersink drill bit - 2-5 mm, 5-10 mm, 10-15 mm, 15-20 mm For cutting metal, wood, plastic, aluminum and thin iron Countersink drill HSS set is suitable for cutting metal, wood, plastic, aluminum and thin iron. Great for drill operations To chamfer the circular opening of the workpiece, conical hole or other DIY work (hardness <25 degrees) With internal chip removal to prevent metal flying phenomena to ensure safety Titanium Coated Titanium coated surface for high hardness, wear resistance, high cutting speed, sharp cutting edges and high toughness Drill a hole accordingly Drill a hole accordingly Chamfers countersink Go with the chamfer countersink Tighten the screw HSS Cut Tool Set for DIY Plastic Wood Metal Aluminum Copper 1/4"(6.35mm) hex shank; work with most drill or drills with 1/4" chuck pilot hole; spiral cutting edge knockouts on metal plug sockets 90-degree Counter Bore Shank Shape The Countersink Chamfer Drill Type, Professional Chamfer Cutters Make Your Job Easy And Make Cutting Effect Is Good For bench drills meanwhile not for hand What is suitable is the best