Robust HSS Cobalt pilot drill with large diameter for greater durability. Reinforced shank and close-fitting guide drill produce less play than conventional systems. Suitable for drilling centre holes in preparation for stable work with hole saws. Tip design offers high speed, long lifetime and improved guidance when drilling, for more accurate results. Ideal for use with metal and stainless steel. For use in conjunction with the Bosch Powerchange Plus keyless arbor (sold separately). Hardened HSS Cobalt Construction 1/4" Hex Shank Suitable for Stainless Steel & Hard Metal Large Diameter for Durability Hardened HSS Cobalt Construction 1/4" Hex Shank Suitable for Stainless Steel & Hard Metal Large Diameter for Durability