The Astro Pneumatic 9445 Titanium Step Drill Bit Set features self-starting multiple hole sizes. All contained drill bits have a 1/4-Inch hex shank for use with drills and quick change chucks. This kit includes 13 Hole Sizes from 1/8-Inch to 1/2-Inch in 1/32-Inch increments, 6 Hole Sizes from 3/16-Inch to 1/2-Inch in 1/16-Inch increments and 9 Hole Sizes from 1/4-Inch to 3/4-Inch in 1/16-Inch increments.