1、High Hardness: Carbide cutter head, possess high hardness, wear resistance and heat resistance, and long service life 2、Meet A Variety of Work Needs: The package contain rotary files with single and double slot design to meet a variety of work needs 3、Smooth Chip Removal: Rotary file drill bit set come with high working efficiency and smooth chip removal, very practical 4、Single Slot For Harder Materials: Single slot is suitable for harder materials such as iron, steel, copper, etc. which is labour saving 5、Double Groove For Softer Materials: Double groove is suitable for softer materials such as wood, aluminum and plastic, with high efficiency 20 x Rotary File Item Type: Rotary FileMaterial: CarbideSurface Treatment: Single and double pattern Ti platingProduct Ratio: Cemented carbide rotary fileShank Diameter: Approx. 3mm / 0.12inHole Position: Approx. 3mm / 0.12inLength: Approx. 38mm / 1.5in