Here we have a wonderful five digit MK VI example, a personal horn of mine that I spent many hours optimizing and overhauling.  This plays with a focused heavy weight buzz and rich colorful character.  The intonation by my estimation is very nice, and complexity is expected at 84xxx.  It is not a museum piece but in very good condition and these 80k sopranos are not getting any easier to find.

This is set up with brass resonators, most are nickel plated, treated pads and has a very nice feel and response.