Features Safe to use: the micro engraving pen is equipped with an integrated safety protection board and an intelligent overload protection chip. If the working resistance is too high, the current will automatically shut off to prevent damage to the engraving Speed adjustable: the speed can be adjusted in three levels in the range of 5,000 to 18,000 rpm and is suitable for different materials. Aluminium alloy material: this engraving pen is made of high-quality aluminium alloy material, is lightweight and is easier to control and use. Practical use: our engraving pen works quietly and does not disturb others. Light weight, easy to carry and convenient to use. 4 HEADS The package contains 4 grinding heads, which you can use according to your different requirements. Specification: Item Type: Electric Engraving Pen Material: aluminium alloy. Battery: 4.2V lithium battery x 1 Battery capacity: 300mAh (comes with built-in battery) Speed: 5000 RPM (Low Speed), 1000 RPM (Medium Speed), 18000 RPM (High Speed) Power: 8W Charging voltage: 5VU Package list:1 x pen4 x grinding head1 x grinding head storage box1 x USB cable1 x manual1 x storage box3 x cutting knife1 x connecting rod2 x drill 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 Box 3 x Cutting Blade 1 x Connecting Rod 2 x Drill Bit