TromboneChat

I randomly came across this trombone online. Never saw a double bell trombone before. And the trigger looks interesting.
https://reverb.com/item/4286063-schiller-studio-bandleader-double-bell-trombone-gold?gclid=CjwKCAjwjJjOBRBVEiwAfvnvBCaihTuxiNtG3Q-REZopfBjFMyQx_25knB9-PnVMLd_a4hlTA_q20RoCrXQQAvD_BwE

When you activate the trigger, does the horn preach the words of Chairman Mao?

No!
Mongolian throat singing is amplified through it 

Looking at the photo, it seems you can convert the trigger to either engage the 2nd bell or be an F attachment by "plugging" the 2nd tuning slide either into the 2nd bell or the extra F tubing.
Weird, but maybe cool for some of those more avant garde folks.

This gets discussed at least once a year, but no one here as ever admitted to buying one.

not a Schiller,  but...

https://www.youtube.com/watch?v=JdkcXoQMFUM

...or,

https://www.youtube.com/watch?v=EEQ9bWCWTRU

Start around 15:10

...or,

https://www.youtube.com/watch?v=EEQ9bWCWTRU

Start around 15:10