Features: Easy to change the strings, clockwise or counterclockwise switch to control string tension. Easy to operate, saving time and effort. Built-in rechargeable li-ion battery, charge via included USB cable. Compact and lightweight, it is easy to store and carry. The electric string winder is easy to change the strings, easy to operate, saving time and effort. It is suitable for folk guitar, acoustic guitar, electric guitar, etc. Suitable for folk guitar, acoustic guitar, electric guitar, etc. Specifications: Winding Speed: Max. 150KHZ Overcharge conservation Voltage: 4.3V Working Voltage: 2.7-4.3V Battery: Li-ion 3.7V 800mah Working Speed: 5rpm/s Charge Time: 2-5h Item Size: 120 x 100mm / 4.72 x 3.94in Color: orange Material: ABS Package Contents: 1 x Electric guitar string winder 1 x Charging cable Due to the lighting problem, there is a slight color difference