Steel Plating Piano Tuning Fork Tool A-440 Tuner 440Hz for Musical Instrument High quality tool useful for setting A440 when tuning a piano or other instrument. Hold curved grip by your thumb and index finger while firmly but briefly striking one of the fork tines on a hard, non-metallic surface to produce a clear tone. To amplify, touch and hold the base end to any solid or hollow flat surface while fork is vibrating. Length: 12.3cm Material: 45 # steel plating