
What's really notable about this instrument to me (apart from the key, obviously) is that it clearly uses no trumpet parts, like most soprano trombones do. The slide is as wide as a tenor slide, and the bell is 6.3" with a big throat like a flugelhorn - in fact, I think they took the bell straight from their Phat Puppy pocket flugelhorn, Shepherd's crook and all. It's not surprising then that they basically call it a slide flugelhorn. While that's technically impossible with that much cylindrical tubing, thanks to the bell it does sound much more flugel-like than most sopranos:
It apparently also comes with a mouthpiece designed for the instrument, and it looks to be a more trombone-sized rim in the above video.
It seems like a weird choice to make a soprano in G, but at the same time soprano isn't a standardized instrument at all so it's not like they HAVE to be in Bb...the positions are very different anyway! And any soprano trombone that is actually designed with intent and not just with using student trumpet parts is automatically very interesting in my book.