IRWIN Unibit 3 8 in 13 Step Drill Bit Planters and Pots 60 Returnable 180 Day Included Mounting 60 Returnable 180 Day Included Mounting Hardware Installation: suspended inlaid 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)