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I have an old Mirafone mouthpiece, standard shank, stamped simply F/Eb, no model number. It came supplied thirty years ago with the then old model 180 F tuba. A specs. sheet I have (issued by Mirafone), lists three models stamped "F/Eb". Can anyone comment with a degree of authority what this model comes numbered at today? Thank you.

I have an "F/ Eb 23" and a newer "23" from Miraphone. The older one has a tighter throat, but the cup and rim seem the same. I got the old one in 1987, there weren't as many mouthpieces designed for F tuba at the time, and my teacher recommended this one. I learned F on it. A bit too oinky for me nowadays.
jc