Happened to stumble across this on ebay. Curious if anyone here has any clue on who did the work. What is the logic at play to mod the valve section over stock in this way? What effect do you think this mod has?

<LINK_TEXT text="https://www.ebay.com/itm/Bach-50BLG-Pro ... 3476525480">https://www.ebay.com/itm/Bach-50BLG-Professional-Bass-Trombone/183476525480</LINK_TEXT>

Maybe John Sandhagen. His personal horn has a similar wrap.

Improved weight distribution (more mass closer to the pivot point), less extension beyond the tuning slide (important in cramped quarters), less of a water trap than a tradition wrap.

Thein uses a similar wrap on some of their bass trombones.

https://thein-blechblasinstrumente.de/07-23-classic.php