Unbranded, unknown 2-inch visual back adapter with M50 threads

This is an unknown 2-inch adapter. It looks a lot like a Stellarvue F060M2 helical focus grip. Except, those units have a tapered bottom where it threds into the prism body.

So, for now, this is a 2-inch visual adapter for either a reflector/refractor/cassegrain focuser that accepts a male 50mm thread (sorry, I cannot calculate the pitch), or for a large, 2-inch mirror/prism diagonal for its viewing port-end.

Beautifully built of thick milled, anodized aluminum and with an internal brass compression ring. Yes, no marring your chrome barrels!

Weighs exactly 3.2 ounces and is exactly 1.89-inches long to include the protruding male threads.

Cosmetics are near perfect mint. No discoloration. No abrasions, scrapes, dings, or dents to see. The rubber texture is perfect and not dry or peeling off. The setscrew is mint and the inner compression ring is true in form.

All nations welcome to bid.....And to find out who made this thing!