Nick, here is the link: VogtlÃ¤ndische Musikinstrumrntenfabrik - Tuben They have a straight G and a G/F with interchangeable bells. I can't imagine that they build a ton of these things, so I am sure that they are all a little different. Maybe I'll get the chance to try one. I'll let you know. Enders died over 20 years ago. Nobody followed in his footsteps. I don't know what happened to his equipment. Every once in a while a horn pops up.