PENSON & CO. HSS Titanium Step Drill Bits Set Metric Sizes Bits Bit Material: High Speed Steel (HSS), Titanium Nitride Coated Drill Bit Type: Twist Shank Style: Tri-flat Number of Pieces: 1 Sizes: 1 PC-6 to 35mm (6, 8, 10,12, 16, 18,20,22,25,28,30,32,35).