The Ref. 5512 from 1959 has just about all the things we would search for on The existing Submariner. Its case had developed to 40mm, up in the 37mm to 38mm of before pieces. Crown-guards have been included, along with the bezel now slightly overhung the side of the case https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/