Tuba/Euphonium
The Euphonium (also known as the Tenor Tuba) is pitched in Bb and reads Bass and Treble Clef.
The Euphonium plays in the same register as the trombone but has a rounder, more mellow sound, similar to the difference between a trumpet and flugelhorn.
The Euphonium is a very capable yet underutilised instrument in the brass family. It has one of the largest usable ranges, is capable of producing a beautiful sonorous tone for melodic roles like the cello and has incredible technical facility meaning it can play very complex music.
It has a range of Bb2 to C5 though some advanced repertoire will go up to F5.