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 carry 1 x String Winder1 x USB Cable Item Type: String WinderMaterial: Plastic + MetalBattery Type: Lithium battery (shipped with built-in battery)Battery Capacity: 800mAhThe Highest Speed: 15KHzOvercharge Protection Voltage: 4.3VWorking Voltage: 2.7～ 4.3VWorking Speed: 5 R/MinCharging Time: 2-5 Hours