These horns are unusual in that they don't have a name stencilled on the bell. The only name on the bell is Max Keilwerth. This is in itself unusual, since none of MK's other horns have his name on them.

This leads one to wonder which of the many MK horns we see were actually made for himself—we know the President was, and ostensibly the Mars was—and which were indeed stencilled for others.

Sadly all the records for Max Keilwerth's company have long been destroyed. It is quite likely the history of this man's remarkable horns will remain an enigma.