3 Pcs Hex Shank HSS Titanium Coated Step Drill Bits Set ,4-/12/20/32mm .Automatically Deburrs Holes as you Drill. Two-flute Design Gives You Faster, Smoother Cutting. Titanium Nitride Coating for Cooler Running, can effectively extend the service life of the drill Widely used to cut holes in a variety of material like steel, wood, thin iron, aluminum alloy,PVC Material : High speed steel .Long life !