ITEM NAME:6PCS Hex Shank Titanium Plated Screw Thread Drill Bits Set Compound Tap TSZ.Combination Drill Tap Bit Set HSS6542 Titanium Coated Countersink Bits. Product List: 6 Hex Shank Tap Drill Bits. Shank: 1/4" (6.35mm) hex shank. Type: Tap Drill Bit. Uses High Speed Steel 6542 material, higher hardness, more durable,can be used for drilling the steel plate even the 2mm 304 steel plate.