The Irwin 29-pc Turbomax Drill Bit Set, No. VG3018006B, covers 1/16" through 3/8" in 1/64" increments, plus 25/64" through 1/2" with reduced shanks in 1/64" increments. This set works on curved surfaces and offers high-speed steel with a black body and gold flute, a self-centering Turbomax tip for clean entry and fast starts, a three-flatted shank on 3/16" and above for better chuck grip, oxide treatment to resist corrosion, which helps prevent the bit from rusting, a reduced shank above 3/8" for the use of larger drill bits in a 3/8" chuck and more.