STRAIGHT FLUTE STEP DRILLS The Titanium Nitride coating significantly increases the tool life by providing the following benefits: Increases surface hardness to 85HRC Ceramic surface reducing friction by up to 30% Especially resistant to cold welding. Suitable for cutting a wide range of materials. Sizes Included:4 5 6 7 8 9 10 11 12mm Step Length:3.75mm Overall Length:65.5mm Shank:6mm