Hello OF,

I'm hoping to identify this case back which came with a Zenith watch I purchased last week. I knew the case back was wrong at the time, and I'm hoping to find the right one. When I do, I hope to be able to solve someone else's problem if they're looking for one like this. There are no maker marks that i can discern. The diameter of the back is 33mm.
Here are pictures of both sides.

Thanks for any help you might be able to offer.

Nick