This EUM-621 looks like another Yahama 621 clone. There's an EUM-721 that's compensating, but I don't see a trigger mechanism on it. It looks like a Besson-style horn.
As far as I can tell, the US-spec model number is 426 for the non-comp and 526 for a compensating horn with Yamaha-style tubing. A bit strange that the same company would have two different bases for this kind of thing, but that's what you get with stencils, I suppose.
Whatever you lose, you'll find it again. What you throw away, you'll never get back.
-- Kenshin Himura
1974 B & H Imperial / Bach 3G -- no LTE mouthpieces for me!