The euphonium is the tenor voice of the tuba family.  It is used in concert bands, military bands, brass choirs, and occasionally in the orchestra.  A euphonium player may also be fluent on the trombone as the mouthpiece size is similar.  As some ensembles have no position available for a euphoniumist, a musician seeking employment as a euphonium player must be the eternal optimist.  The euphonium may have 3, 4 or 5 valves, and may have an upright or front facing bell.  This instrument differs from the baritone horn due to the euphonium's larger bore and more conical main bugle.  Euphoniums are available in British, German, and American styles.  The German model, usually seen with rotary valves, is often known as the tenor tuba, but the three styles of instruments are interchangeable in most ensembles.