Tuba mutes

Tuba mutes – A variety of mutes for your tuba which can be used in a range of settings from performance to practice. Anything from mutes on a budget right through to professional level mutes for the concert stage, we stock various Tuba mutes for all budgets and occasions. Practice mutes are becoming ever more popular for their ability to allow the player to practice anywhere with minimum disturbance. The straight, cup and harmon mutes are real essentials to any musicians collection.  Denis Wick produce wooden mutes for Eb or EEb basses and Bb or BBb basses.
On that subject, what is the difference between an Eb bass and a double or EEb bass? Answers on a postcard. Is it the bore size? Does the single have three valves and the double four valves? They both have the same length of tubing so it’s not that. So what is the difference?