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French tuba, euphonium, etc?

It is a Saxhorn basse en Si bemol. Which is the French equivalent of the British euphonium, only the French used up to 6 valves rather than the compensating system.

From the looks the valves lower the instruments by these interevals:
1: whole step
2: semitone
3: two whole steps
4: fourth
5: fifth

There are variants where the 5th valve is identical to the 2nd valve, That goes for my own de Prins, but I pull that slide so that it becomes a long semitone like the 6th valve on F tubas.

Klaus