Feature: 1. Secure And Reliable: This electric rotary tool has a built in security guard circuit board and an intelligent overload guard chip. When the working resistance is too large, it will automatically cut off the power supply to prevent damage to the engraving pen, which is very secure to use. 2. Stepless Speed Adjustment: This cordless rotary tool kit has stepless speed adjustment, which can be adjusted within the range of 0‑16000r/min, and can be turned forward and backward according to the demand, which is suitable for different materials. 3. High Performance Motor: This mini engraving tool is powered by a high performance motor that provides better control and maneuverability and polishes very efficiently. The lightweight frame and ergonomic grip provide you with accurate fingertip control. 4. Compact And Lightweight: This cordless rotary grinding tool is small in size and light in weight, very convenient to carry and use, and the noise is very low when it works, so you don't have to worry about affecting your family's rest. 5. Wide Application: This battery powered rotary tool has a wide range of applications and is suitable for performing a variety of home projects or manual work such as grinding, cutting, lapping, engraving, polishing, drilling and more. Specification: Item Type: Cordless Rotary Tool Kit Material: Aluminum Alloy, ABS Battery: 20V Lithium Battery x 1 (Not Included) Battery Adapter Specs: DC 21V 0.8A Output Interface: DC Interface, 5.5 x 2.5mm or 5.5 x 2.1mm Speed: 0-16000 RPM Support: Forward and Reverse Compatible Batteries: for BL1815, for BL1820, for BL1830, for BL1840, for BL1850, for BL1860, for BL1845, for BL1890. Package List: 1 x Cordless Rotary Tool 2 x Wrenches 1 x Chuck Shaft 1 x Rubber Wheel 1 x Tapping Screws 1 x Circular Saw Blade 2 x Diamond Grinding Needles 2 x Wool Polishing Wheels 3 x Sandpaper Rings 3 x Twist Drill Bits (0.5, 1.0, 1.5mm) 5 x Grinding Wheel Bits 1 x Storage Box 1 x Manual