#3 Unibit, 1/4" To 3/4" Step Drill, 9 Hole Sizes From 1/4" To 3/4" In 1/16" Increments, Maximum Material Thickness 1/8", 3 Flatted Shank, Shank Size 3/8", Single Fluted Cutting Edge Assures True Round Holes & Allows Greater Control, Carded.