This lovely EEb Besson Sovereign (model 982) started out in life as a normal brass lacquered  tuba - but someone decided it should join the ranks of colored trumpets, etc. and it was lacquered blue. The inside of the bell (see below) and other trim remains gold brass.  I saw it on eBay and couldn't resist ( even though I already owned a silver EEb Sovereign!)  I recently shipped this beauty to a discriminating tubist in Japan who plays in a street band!!