The Ref. 5512 from 1959 has nearly every little thing we'd look for on the current Submariner. Its case had developed to 40mm, up in the 37mm to 38mm of before items. Crown-guards were being added, as well as the bezel now a little overhung the facet of the case https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/