#4 Unibit, 3/16" To 7/8" Step Drill, 12 Holes Sizes From 3/16" To 7/8" 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.