The Ref. 5512 from 1959 has pretty much all the things we would hunt for on the current Submariner. Its circumstance had grown to 40mm, up in the 37mm to 38mm of earlier pieces. Crown-guards were being added, and also the bezel now marginally overhung the aspect of the case https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/