Why would they put a re-ring at the 8" point of the drum? Did they do that for the 16x16 floor toms?
I don't know, but I read that Slingerland discontinued making shells with three rings in 1941 and at one point they did offer 16x14 floor toms. Maybe that's how they made that particular size. Whatever the origin, it's a cool drum and I'm guessing fairly rare.