Item Type: Guitar String Button Material: ABS Plastic Handle + A3 Steel Plate + Iron String + Copper Gear Features: 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 Package List 3 x Right Guitar String Button 3 x Left Guitar String Button 12 x Screw 6 x Other Accessories 1It is a system that is automatically locked by string tension, which is very useful when tuning a guitar with vibrato without interruption and slipping. 2Suitable for guitars, folk guitars, acoustic guitars, cigar box guitars and other highquality opengear tuner. 3Suitable for threeway alignment (both sides of the spindle box), very practical and durable in use. 4It has a variety of functions, such as wear resistance, anticorrosion and antirust functions. 5Adopting ABS plastic handle, A3 steel plate, iron string and copper gear material, reliable quality.