The Ref. 5512 from 1959 has nearly almost everything we'd try to find on The present Submariner. Its case had grown to 40mm, up from the 37mm to 38mm of before pieces. Crown-guards have been additional, as well as the bezel now a bit overhung the aspect of the case https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/