The Ref. 5512 from 1959 has pretty much almost everything we might try to look for on The present Submariner. Its case had grown to 40mm, up with the 37mm to 38mm of earlier items. Crown-guards were included, and the bezel now a bit overhung the aspect of the situation https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/