Johann Michl & Sohn - Graslitz - Sudetengau F tuba 4RV (the engraving dates it to between the Munich agreement of 1938 a

1. Full view

2. Tuning slide pulled

3. Back view

4. Body view

5. Body back view

6. Valve section

7. Clocksprings

8. Kranz

9. Bell engraving
The engraving dates this tuba to between the Munich agreement of 1938 and the end of WWII