Item Type: String Winder Material: Plastic and Metal Battery Type: Lithium battery (shipped with built-in battery) Battery Capacity: 800mAh The Highest Speed: 15KHz Overcharge Protection Voltage: 4.3V Working Voltage: 2.7-4.3V Working Speed: 5 R or Min Charging Time: 2-5 Hours 1,The multi-function winder can be used to wind or tighten the strings of any instrument 2,Suitable for guitar, banjo, violin, bass, suitable for most acoustic and electric guitars and any other stringed instruments 3,The unique shape of the puller can work easily and happily without damaging the guitar bridge 4,Electric winder and reliable thread cutter, simple operation, time-saving and labor-saving, convenient for daily use 5,Due to the compact and lightweight design of the multi-function winder, very easy to store and carry1 x String Winder 1 x USB Cable Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.