IRWIN Unibit 3 8 in 13 Step Drill Bit Planters and Pots Shelf brackets are compatible with Shelf brackets are compatible with wood capacity and includes screws 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 wood and laminates 3 flatted shank won't slip in chuck Speed point tip for fast starting Laser marked sizes won't wear off with use Unibit #3 is engineered with M35 cobalt steel for maximum life when drilling in tough steel Unibit #3 cobalt contains a 3 8 in hex shank and contains 9 hole sizes 1 4 in 3 4 in (1 16 in steps) Unibit #1 contains a 1 4 in hex shank and will drill 13 hole sizes 1 8 in 1 2 in (1 32 in steps) Unibit #4 contains a 3 8 in hex shank and will drill 12 hole sizes 3 16 7 8 in (1 16 in steps)