The Ref. 5512 from 1959 has pretty much all the things we would try to find on the current Submariner. Its case experienced developed to 40mm, up through the 37mm to 38mm of previously pieces. Crown-guards were additional, as well as bezel now somewhat overhung the side of the case https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/