The irwin 19 piece metric turbo max drill bit set suitable for portable and cordless drills they are primarily designed for drilling metal and sheet metal but also perform exceedingly well in all types of wood and plastics and can be used for drilling stainless steel please note that if used for drilling stainless steel a coolant should be always be used sizes 1 15 2 25 3 35 4 45 5 55 6 65 7 75 8 85 9 95 and 10mm