IRWIN Unibit 3 8 in 13 Step Drill Bit Planters and Pots while the powder coated finish prevents while the powder coated finish prevents wear and tear to the nailer's body capacity and includes screws Single fluted cutting edge for greater control and rounder holes Ideal for drilling holes in thin materials such as mild steel 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)