In 1918, accoding to the Boosey website, Buffet started selling horns under their own name in the US. These MAY be those horns.

Techie notes:
- Pearl keys are introduced
- Horns have a unique serial number chart, starting at s/n 1 or 100.
- Horns otherwise appear identical to other post 1895 Evette & Schaeffer horns.

I believe these horns were produced until about 1933. Around this time, Buffet started marketing the Evette as a primarily student-model line.

In any event, around 1933 the Buffet-Powell horns were introduced and they seem to follow the original Evette & Schaeffer serial number charts.