It's basically the same thing

Pretty much, although it features a decorative bell in suggestion of a open end. I'm treating it as a plastic gemshorn, but the tone is pretty severe. It also has a plungeable mouthpiece by which one may drop the entire instrument down to D; very useful, probably like those plungers on your ocarina page. Love the metal ones by the way; there was one on sale in an antique shop in Barnard Castle a couple of years back but I was broke at the time and had to pass.

I'll send you some pics when I get sorted.