Picture of large rotary valve?

[marccromme]

I have recently seen a picture of a large rotary valve, kind of a painted diagram with green color indicating the inside tubing. It is machined out of massive nickel silver, I think, a d seems otherwise greenhoe like. I can't remember the name of the valve, or the location of the image, can anybody help?

[hyperbolica]

Facebook. Rath R6 valve.

https://trombonechat.com/viewtopic.php?f=13&t=13034

[marccromme]

Thanks, much appreciated!