Feature:1. SAFE TO USE: Micro engraving pen is equipped with a built in safety protection circuit board and an intelligent overload protection chip. When the working resistance is too high, the power will be automatically cut off to prevent damage to the engraving pen.2. SPEED ADJUSTABLE: 3 level speed can be adjusted within the range of 5000 to 18000 r/min, suitable for different materials.3. ALUMINUM ALLOY MATERIAL: Made of premium aluminum alloy material, this engraving pen is light in weight and is easier to control and use.4. CONVENIENT USE: Our engraver pen operates with low noise, and will not disturb others. Light weight, easy to carry around for convenient use.5. 4 HEADS: There are 4 grinding heads in the package that you can use them respectively to meet your different needs.Specification:Item Type: Electric Engraving PenMaterial: Aluminum AlloyBattery: 4.2V lithium battery x 1Battery Capacity: 300mAh (shipped with built in battery)Speed: 5000rpm (low speed), 1000rpm (medium speed), 18000rpm (high speed)Power: 8WCharging Voltage: 5VU.Package List:1 x Pen 4 x Grinding Head 1 x Grinding Head Storage Box 1 x USB Cable 1 x Manual 1 x Storage Box3 x Cutting Blade 1 x Connecting Rod 2 x Drill Bit