Vintage Rolex Submariner Brochure
[Reference 5513]
"In the twilight of the deep waters one of the most vital items of a diver's equipment is his watch. The "Submariner" was the world's first watch designed especially for skin and deep sea divers, 100% waterproof to a depth of 660 feet, is has a calibrated outer bezel which allows the accurate and correct timing of decompression periods."