Features 1、SAFE OPERATION: This carving pen has a safe protection circuit board and smart overload chip, which will automatically cut off the power supply when the working resistance is too high. 2、HIGH CONCENTRICITY: Built in precise bearings and extended rotating shaft, effectively improving rotational concentricity, and the interchangeable copper chuck ensures stable clamping. 3、3 SPEED ADJUSTMENT: This electric grinding pen has 3 levels speed adjustment range of 5000-1800rpm, suitable for different materials and has a wide range of applications. 4、LOW NOISE: This tool is lightweight and portable, with low noise during operation and will not affect other work, suitable for grinding, polishing, and engraving, etc. 5、BUILT IN BATTERY: This electric grinding pen is rechargeable, with a built in 300mAh lithium battery and a USB cable, making it convenient for you to use anytime, anywhere. Specification Item Type: Electric Grinder Pen Material: Aluminum Alloy Battery: 1 x 300mAh 4.2V Lithium Battery (built in battery) Speed: 5000rpm (low speed), 10000rpm (middle speed), 18000rpm (high speed) Power: 8W Package List 1 x Grinding Pen 5 x Grinding Heads 2 x Wool Wheels 1 x Charging Cable