Inton M2 Material 6pcs HSS 1/4 Inch Hex Metric Deburr Countersink Titanium Coated Combination Drill Tap Bit Set M3-M10 (6pc titanium) Type: Tap Drill Bit (Top Five Review have chance to get 50% discount, see review then contact u about the discount). Shank: 1/4" (6.35mm) hex shank Material:M2---High hardness, rustproof, solid and durable. Surface Treatment: Titanium Coated & DIY Supplies: Metalworking Size: M3, M4, M5, M6, M8, M10.