Be sure to print in this orientation
Attach it to your horn at the 3rd-valve slide and rest the other side where the lead pipe enters the 3rd valve.
I've also added a set screw hole for an M3 screw.
The *.f3d file is attached - please remix!
The author remixed this model.
I changed the attachment point and method to better suit my horn and a straight lyre. This could possibly make it more universal.