Zenith Vintage Chronograph 143-6.
Some pictures of this lovely vintage Zenith Chrono, housing a Cal 143-6... I wonder if it is not an Excelsior Park movement, by the way.
I am not an expert in vintage Zenith watches, but I think some of these were issued to the Yugoslavian Army.
Always a pleasure to see stuff like this, even if this one has suffered a bit.