Features:1. 100% brand new high quality rotary drill grinder set, strictly full tested to ensure the best quality before shipment, safe to use2. The USB electric grinding set is processed by professional manufacturing, it has precise design, strong power output, high working efficiency3. The engraving kit is designed with USB power supply, can be plugged into mobile power supply, power adapter, even computer and other devices, can be used anytime, anywhereSpecification:Grinding head diameter: 0.5-3.2 mmChuck size: 0.5-3.2 mmNo-load speed: 15000 rpmMaximum power: 20WNo-load speed: 15,000 rpmClamping range: 0.5-3.2MM (can be replaced by yourself)Product dimension: 15.5*2*2cm / 6.1*0.8*0.8inWeight: 182g / 6.4ozCharging Tip: Charging indicator No. 1 red light is on until the red light of No. 1 turns green, indicating that it is fully charged; the battery is running out of red light.Package list:3 * Drill(0.5/1.0/1.5mm)3 * Small sandpaper circle6 * Copper chuck(one is installed in the machine)1 * Small wool wheel1 * Big wool wheel1 * Stainless steel slice1 * T-type Flint2 * Cone grinding head1 * Spherical grinding head1 * Cylindrical grinding head1 * Sandpaper ring1 * Wool connecting rod2 * Grinding needle1 * Red gasket connecting rod1 * Electric Grinder1 * USB cable