Hello,
I ran across a horn at an estate sale that played decently and got it. However, I can't find any information on its history or brand. It's engraved "Topper" and "Made in U.S.A." on the back of the bell. As far as I can tell, it appears to be an American-style euphonium similar to some Conns and Kings (3 front action pistons with a front facing bell). I measure the bore ID at the valves to be about 0.55". Does anyone know about this brand or its horns?

opper1.jpg
opper2.jpg
opper3.jpg

Thanks,

Jacob
Meinl Weston 2011FA BBb HoJo
GW Baer MMVI
GW Szentpali
PT-50
Schilke Helleberg