This diamond Drill Bit Sharpener Stone is mainly used for grinding iron drills, not suitable for other high hardness drills. Lightweight and compact size, the drill sharpening Stone is made for using in drill sharpening Tool. Improve drill bit usage, small and portable, practical tools. Lightweight & Compact: Lightweight and compact size, the drill sharpening tool hand crank drill bit sharpener is easy to carry. Made of high-quality brown corundum grinding wheel, High hardness, rustproof, solid and durable.