4 kinds of specifications - 2-5mm, 5-10mm, 10-15mm, 15-20mm HSS 4241 below 65HRC - HSS 4241, high hardness and wear resistance, high cutting speed, sharp cutting edges. For materials with hardness below 65HRC Design 90 degree design - The countersink drill has the advantages of wear-resistant and durable chamfer concentricity, beautiful chamfering, etc. Design Angular design - Rust and corrosion resistance. Strength and sharpness of the edges increase the use of large core diameters, tool rigidity, milling and cutting performance For all common drills - Drills from Hilti, Bosch, Makita, Hitachi, Fein, AEG, Metabo, DeWalt, Schwarz & Decker, Brüder Mannesmann, Kress, Wolfcraft, Einhell, Milwaukee, Flex and many others (use rust protection oil)