Locking Nut

This is a type of guitar nut design that clamps the strings in place in order to maintain tuning when using a vibrato tailpiece. Typically, screws are tightened against small pieces of metal, which squeeze the string(s) against the base of the nut. While locking nuts can often eliminate tuning problems associated with “vigorous” whammy-bar usage, the tradeoffs can be difficulty tuning; difficulties if a string breaks or stretches during a performance; and, according to some players, tonal changes as compared to a bone or synthetic nut. (Though other players prefer the sound of locking systems versus non-locking systems. Viva le difference!)