Natural horn. No valves. Use your lips and hand. The old ones were painted inside the bells. We used them for a couple of Handel pieces recently.

And every once in a while our 'leader/teacher' Dr. Hank picks up a regimental horn that might have a crook to change from one key to the other, but often in F and he just improvises with us and leads with the other hand. It always sounds good, but I guess being a brass professor it should eh?

John Conley
Musica est vita