Stable speed, high concentricity, low vibration, reducing the loss of components, and more . The pen's small size, light weight and design are all designed for better one-handed operation Variable speed throttle control for any speed up to 70000 RPM and has a self-closing lever. Suitable for precision grinding of various metals, grinding of various welding surfaces, sculpture of plastics, stone, wood, etc. After-sales service, Please contact if you have any questions