Suitable for the following metals: Aluminium, Aluminium Alloy, Copper, Platinum, Silver, Gold, Titanium, Zinc, Alloys, Chrome, Tin, Aluminium Profile, Steel/Ferrous Metal, Unalloyed/Low-Alloy Steel, High-Alloy Steel and Gray Iron. The Bosch 2608596816 Pack Of 5 have a 4.0mm diameter, a working depth of 78mm and an overall length of 119mm. The HSS Twist Drill Bit Ground is for drilling through metal with maximum precision. The bit's exposed 135-degree self-centring split-point tip combines active cutting and perfect centring without wandering, delivering maximum precision. The split-point tip also eliminates any need to pre-punch or pilot drill for up to 10 mm. This precision-ground bit made of HSS (high-speed steel) enables up to 40% faster drilling rate and up to 50% lower feed pressure than standard-ground HSS drill bits with chisel edges. This bit is designed for drilling holes in alloyed and non-alloyed steel, cast steel, cast iron, sintered iron, malleable cast iron, non-ferrous m