But I know the difference - A) real French horns haven't had piston valves in nearly sixty years, and; B) real French horns are much more twisty, and, worst of ALL; C) that picture looks suspiciously like you're using a TRUMPET mouthpiece. Sacrilege! Blasphemy! Good lord, girl - run, don't walk, down to your local music store and demand an adapter so that you can use a REAL horn player's mouthpiece! ;)
LOL! No, I usually use a french horn mouthpiece for that thing, but that night i used a trumpet mouthpiece cos i left my horn mouthpiece in my concert horn case. y'know. or heck, that might have been my horn mouthpiece....hm....oh well.