#1 Unibit, 1/8" To 1/2" Step Drill, 13 Hole Sizes From 1/8" To 1/2" In 1/32" Increments, Maximum Material Thickness 1/8", 3 Flatted Shank, Shank Size 1/4", Single Fluted Cutting Edge Assures True Round Holes & Allows Greater Control, Carded.