Bigsby

The Bigsby vibrato tailpiece is a type of vibrato device for electric guitar designed by Paul A. Bigsby. The device allows musicians to bend the pitch of notes or entire chords with their pick hand for various effects.
The Bigsby was the first successful design of what is now called a whammy bar or tremolo arm, although vibrato is the technically correct term for the musical effect it produces. In standard usage, tremolo is a rapid fluctuation of the volume of a note, while vibrato is a fluctuation in pitch.