Features: 1.It is a system that is automatically locked by string tension, which is very useful when tuning a guitar with vibrato without interruption and slipping. 2.Suitable for guitars, folk guitars, acoustic guitars, cigar box guitars and other high?quality open?gear tuner. 3.Suitable for three?way alignment (both sides of the spindle box), very practical and durable in use. 4.It has a variety of functions, such as wear resistance, anti?corrosion and anti?rust functions. 5.Adopting ABS plastic handle, A3 steel plate, iron string and copper gear material, reliable quality. specification:Item Type: Guitar String Button Material: ABS Plastic Handle + A3 Steel Plate + Iron String + Copper Gear Divided Into Left and Right, Single-Hole Steel Column (Column Diameter 6mm / 0.24in), The Hole is Near the Front End of the String Column. Plastic White Square Head Remark: Each string button comes with 1 white plastic ring and 2 screws PackageList: 3 x Right GuitarString Button 3 x Left GuitarString Button 12 x Screw 6 x Other Accessories