The clavichord is unique because it is the only keyboard instrument where the player remains in direct contact with the string throughout the note. When a key is pressed, a metal blade (tangent) strikes the string and stays there. This allows for a unique effect called 'Bebung'—a finger-vibrato that can change the pitch and volume of a note after it has been struck. However, the clavichord is extremely quiet, making it unsuitable for public concerts; it was designed as an intimate practice instrument for the home. It was a favorite of J.S. Bach, who loved its sensitivity.