This mini electric grinder is made of high quality copper, rubber, plastic, sand and metal materials, sturdy and durable, built in high speed DC motor, suitable for low power operation. The copper sleeve of motor adopts hollow design and built in lubricating oil, which makes it more durable and practical. Feature: 1. MULTI FUNCTION: This electric engraving pen can be used to repair tires, polishing, safe and reliable, low voltage, fast rotate speed, energy saving and practical. Small and convenient to carry, can quickly repair tires. 2. HOLLOW DESIGN: The copper sleeve of motor adopts hollow design and built in lubricating oil, which makes it more durable and practical. 3. LOW POWER OPERATION: This mini electric grinder is made of high quality copper, rubber, plastic, sand and metal materials, sturdy and durable, built in high speed DC motor, suitable for low power operation. 4. UNIVERSAL AT BOTH ENDS: The grinder pen machine is universal at both ends of red and black, regardless of positive and negative. Connect the power supply can be used, the power supply does not distinguish positive and negative poles. 5. EASY TO USE: Tyre repair grinder is easy to use and fine workmanship. Without any difficult requirements even though you use it for the first time. Specification: Item Type: Electric Grinding Pen Weight: Approx.293g / 10.3oz Material: Copper, Rubber, Plastic, Sand, Metal Power Supply: 12V, 24V Speed: 14000 RPM Motor: Bidirectional, DC Motor Power: 350mA Package List: 1 x Electric Grinding Machine