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.
The euphonium outlook is good. Adams E1 and Sonic are in stock; E2 and E3 arrive soon. Miraphone M5050 is available in several options.
Willson is always several months out; I'll let you know. Tenor tubists will be glad to know the Alexander 151 is in stock.