Drillpro Industrial 3-12 4-1 Step Drill Bit Set features a 1/4 inch hex shank and is built from HSS titanium-coated steel. The product title lists the included sizes as 3-12 and 4-1, identifying the stepped bit ranges in the set. This set is a step drill bit collection designed for progressively enlarging holes with a high-speed steel and titanium-coated construction.
