The metabo hss co drill bit set is suitable for drilling in steel va steel cast steel non ferrous metals plastics and special alloys up to 1100 nmm tensile strength the bits are made from a cobalt alloy with a ground cylindrical type n 135 crosswise grinding tip and bronze coloured surface finish they are supplied in a metal tin and it contains one of each size 1 15 2 25 3 35 4 45 5 55 6 65 7 75 8 85 9 95 10mm