Tuba/Euphonium
\
Even the mighty Tuba has a mute!
Tuba mutes are the largest and most expensive of all Brass mutes (some costing as much as a beginner level Trumpet!). Due to this they are the rarest brass mute and not all tuba players will have access to one.
The sound difference between a muted and an unmuted tuba is subtle and often lost in larger orchestral textures, it is best used in solo and chamber ensembles where the Tuba plays a more prominent and exposed role.