1、MULTIPLE USAGES: 3.7V cordless rotary tool kit, portable pen type design for sanding, engraving, polishing and cleaning etc., suitable for home and craft projects. 2、5 VARIABLE SPEEDS: The grinder pen has 5 variable speeds, 3600r/min, 8000r/min, 12000r/min, 15000r/min, 18000r/min, suitable for different DIY work situations. 3、USB AND BATTERY: The tool supports charging with DC 5V USB connector, and equipped with a 1000mAh large capacity battery, suitable for long term operation. 4、OTHER PARTS: Equipped with abrasive rings, chucks, grinding rods, cotton wheels, saw blade, twist drills and connecting rod, etc., this set is convenient and practical. 5、EASY OPERATION: The electric grinder pen is small and compact, easy to operate, ready to use after installing the grinding head, has a wide range of applications.