This Milwaukee drill bit set comes with 16 pieces, all made of high-quality steel and suitable for use with both drills and rotary tools. With a diameter of 4 inches and a length of 2 inches, these black bits are perfect for a range of home and workshop DIY projects. The brand is well known for its durability and reliability, and this set is no exception. Whether you’re a professional contractor or a weekend warrior, these bits will get the job done right. Add them to your toolkit today! Cobalt Drill Bit Sizes. 3/8, 5/16, 3/16, 5/32, 9/64, 1/16. Red Helix Titanium Impact Drill Bit Sizes. Double sided Impact Bit. 2 3/8 Phillip and Flat. Brad Point Bit Sizes. 1/2, 7/16, 3/8, 5/16, 1/4.