The Submariner 6536-1 was launched in 1955 and remained in production until 1959, for only five years. The model was introduced after reference 6204, together with reference 6538 featuring a bigger crown.The present watch represents a very early and rare variation of the model, showing the sought-after "Red Depth" writing, with two numbers separated only by a dash an no meters/feet specification, later introduced. Red Depth 6536-1 Submariners represent the first iteration of the now iconic depth rating, still employed -of course updated to current ratings- on Submariners and Sea-Dwellers.