Drill bit set hss-co stepcut ø2-3-4-5-6-8 mm. 6 pieces in a case with step cut tip special for drilling in tubes, curved and unstable surfaces. the tip does not slip. made of hss co 5% according to din 338. type n 30° helix. for diameters larger than 5 mm anti-slip three-flat shank to prevent chuck slippage due to stress. specific for work on tubes, curved and unstable surfaces in stainless steels, steels and general metals up to 120 kg/mm²