The Submariner is one of Rolex's most iconic models. Still in production today, it has gone through multiple incarnations throughout its 65-year history. While the first generation models had a ‘small’ or ‘large’ crown, in the mid-1960s Rolex gradually introduced crown guards to make the model more robust and durable.Reference 5508 was produced between 1958 and 1962. This model of Submariner, nicknamed the ‘Small Crown’, was the last to have a depth of 100 metres and no crown protectors.