IRWIN Unibit 3 8 in 13 Step Drill Bit Flooring new 15 Mail Slot dimensions: 13 5 8 in Solid Braided Cord Mail Slot dimensions: 13 5 8 in tool combo features an exclusive Heavy Duty Raise and Release latching system that keeps drawers tightly closed Sub Brand Unibit Brand Model Compatibility Universal Number of Hole Sizes 12 Diameters of Holes Drilled 1 8 in to 1 2 in Step Size 1 8 in Shank Size 3 8 in Shank Type Hex Material Black oxide coated HSS Set Individual Set Package Quantity 3 Warranty None CA Residents: Prop 65 Warning(s) Yes Single fluted cutting edge for greater control and rounder holes Ideal for drilling holes in thin materials such as mild steel