Originally Posted by MFfan

I don't know. Even more obscure instrument, I guess, with only the one photo and no detail there. Looks like a common design of many trumpets in early 3rd of 20th century. I wouldn't want to be definitive on the quality, but it well may be a student horn, as it is not listed in the 1913 model list on Horn-u-copia. Monopole was their usual name for top line horns. It looks similar to a Beaufort American horn I briefly had, made in Czechloslovakia for Sears, Roebuck. Maybe someone else will chime in.