Hermann Trapp of Neukirchen in Bohemia F helicon 3RV

1. Valve section view #3

2. Slides

3. Valve section view

4. Maker’s shield

5. Details view #2

6. Valve section back view

7. Disassembled

8. Bell view #3

9. Bell view #2

10. Bell view

11. Valve section view #2

12. Details

13. Bell view #4

14. Bow guard

15. Leadpipe view

16. Large bow view

17. Valve section view #4