Designed specifically for impact drivers where a hex shank is required, Millner-Haufen's hex shank multi-purpose drill bit set includes 3/32”, 1/8”, 5/32”, 3/16” and 1/4” diameter bits. Millner-Haufen multi-purpose bits work well with a variety of materials, so you don’t have to buy a different bit for each job. Effective on: hardened steel, cast iron, concrete, brick, fiberglass, glass, granite, marble, porcelain, and ceramic.