The Ref. 5512 from 1959 has just about all the things we would seek out on the current Submariner. Its case experienced developed to 40mm, up in the 37mm to 38mm of earlier pieces. Crown-guards ended up included, and also the bezel now somewhat overhung the side of the case https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/