It looks reminiscent of the early subsecond Seamasters of the late 1940s/early 1950s. I’ve seen these referred to as pre-Seamasters or Calatravas. Were these indeed the predecessors of the Seamaster and thus manufactured prior to them? How do these compare in rarity and value to their “Seamaster” labeled counterparts? Everything except the crown seems original on this example.

 

Thanks @gatorcpa - is there any significance to “Swiss” vs “Swiss Made” regarding the market this iteration was sold in? My recollection was that later Seamaster iterations that said “Swiss Made” were geared toward Europe while “Swiss” was marketed for the US.