This watch looks like an old Vostok Amphibian in the oldest 350 case and with the oldest aluminum bezel but it’s much more special than that. The case is in chromed brass as opposed to all other Vostok Amphibians that I’ve seen before. Even the caseback looks like many of the casebacks from Vostok but it’s a bit different in its shape. I’ve seen watches that are believed to be prototypes of the oldest model of Vostok Amphibian. Those watches has the caseback turned a quarter of a turn compared to the traditional placement on all other Vostok Amphibians.
I don’t know if this is a prototype of the oldest Vostok Amphibian or if it’s one of their first watches that were made.
It’s a 350 case with the old aluminum bezel. The hands are not what we usually see on Vostok Amphibians but it’s the same hands as on the other prototypes that I’ve seen. The watch is powered by a 2209 movement. Swing lugs. The dial has the cyrillic logotype.

Follow this link to see more photos of this watch: Vostok Amphibian 2209, Prototype