Titanium Step Drill Bits Cone Cutting Set Wood Iron Metal Drilling 1/4" Hex Shank 3-12mm: 3/4/5/6/7/8/9/10/11/12 MM 4-12mm: 4/6/8/10/12 MM 4-20mm: 4/6/8/10/12/14/16/18/20 MM 4-32mm: 4/6/8/10/12/14/16/18/20/22/24/26/28/30/32 MM - Automatically Deburrs Holes As You Drill - Two-Flute Design Gives You Faster And Smoother Cutting - Titanium Nitride Coating For Cooler Running - Quick-Change 1/4" Hex Shank - High Speed Steel For Long Life - These Step Drill Bits Are Ideal For Variety Of Materials From Metal, Plastic, Fiberglass To Wood - They Also Help To Enlarge Existing Holes - The Two Flute Design Tips Can Make The Penetration Faster Without Chipping Variation of Package: Step Srill Bits - 3-12mm - 4-12mm - 4-20mm - 4-32mm -1pc 1/4" Socket Adapter