IRWIN 3 8 in 12 Step Drill Bit Flooring Samples A galvanized steel base supports DuraStone A galvanized steel base supports the tub and ensures long lasting quality tempered glass with solid brass pivots and anodized aluminum profiles Sub Brand NA Brand Model Compatibility Universal Number of Hole Sizes 12 Diameters of Holes Drilled 3 16 in to 7 8 in Step Size 1 16 in Shank Size 3 8 in Shank Type Hex Material Cobalt Set Individual Individual Package Quantity 1 Warranty None CA Residents: Prop 65 Warning(s) Yes wood and laminates 3 flatted shank won't slip in chuck SpeedPoint tip for fast starting Laser marked sizes won't wear off with use