This engraver machine is easier to change bits than others. Without using any tools, just insert the bit and remove directly. Also it is designed for low noise and portable,no worrying about affecting your family while working.Perfect for beginners or to use and convenient to take and then let it customize and create your daily ,such as the special gifts or accessories you . Up to 20,000RPM with a speed control button, adjust the speed as your own . 3 Levels Adjustable Speed in total and it can be adjustable from 5000-20000 r/min for different materials. Press ,5000-10000r/min.Press twice,10000r-15000r/min.Press three ,15000r-20000r/min.The lowest speed will let you do Jewelry and jade art works,and also can make you polish your nail in safe,the highest speed can work on wood, glass,metal,plastic carving. Multi-Function grinding engraving works with precision and comfort on nearly any surface-It is perfect for kinds of material engraving and grinding,such as wood,stone,,egg,crafts,glass,, plastic,nails polishing,sporting ,toys,phone chargers,delicate jewelry,and glassware. 40g for the pen, lightweight and easy to operate for working. So it is easy to hold and use for beginners, it is very stable while you are drilling precisely and carving delicately due to the clamping stability and high concentricity of this graver pen's primary design. Also high-capacity 380MAH battery to on your working more time and persistent power. Our engraver tool for metal is rechargeable,come with USB cable.The mini -engraver pen is built-in safety protection circuit board and intelligent overload protection chip.When the working resistance is too ,it will automatically cut off the power to prevent from damaging the engraving pen, be relieved to use it safely. Electronic Engraving Pen Product's Introduction: 1. Apply to Many Occasions: mini engraving tool kit, you can DIY anytime, and engraving, polishing or drilling on glass, jewelry, plastic, and other surfaces. 2. Three Level Speed Adjustable: Speed 1: 5000-10000 Rpm/Min Speed 2: 10000-15000 Rpm/Min Speed 3: 15000-20000 Rpm/Min 3.Overload Protection:Resistance is too , the overload indicator light is on and automatically cut off for self-protection Material: Metal colour: silver Package Contents: 1 x Engraving Pen 1 x USB data cable 2 x grinding heads Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.