Hermann Trapp of Neukirchen in Bohemia F helicon 3RV

Sep 14, 2009
1. Valves rear
2. Back
3. Hermann Trapp - Neukirchen - Böhmen. The bell diameter is 10.5 inches
4. Receiver
5. Front
6. Body
7. Valves
8. Kranz
9. Disassembled