String instrument strings, or play them by rolling the bell of a brass instrument such as a trombone on the array of strings. However, these are relatively rarely used special techniques. Other keyed string instruments, small enough for a strolling musician to play, include the plucked autoharp, the bowed nyckelharpa, and the hurdy-gurdy, which is played by cranking a rosined wheel. Steel-stringed instruments (such as the guitar, bass, violin, etc.) can be played using a magnetic field. An E-Bow is a small hand-held battery-powered device that magnetically excites the strings of an electric string instrument to provide a sustained, singing tone reminiscent
Hurdy-gurdy types of hurdy-gurdy, notably the French "vielle à roue" ('fiddle with a wheel') and the Hungarian "tekerőlant" ("tekerő" for short), makers have added a buzzing bridge—called a "chien" (French for dog) or "recsegő" (Hungarian for "buzzer")—on one drone string. Modern makers have increased the number of buzzing bridges on French-style instruments to as many as four. This mechanism consists of a loose bridge under a drone string. The tail of the buzzing bridge is inserted into a narrow vertical slot (or held by a peg in Hungarian instruments) that holds the buzzing bridge in place (and also serves as a