ROLEX SUBMARINER MILSUB REF. 5517 IN STAINLESS STEEL - From 1978 Reference N° 5517 Serial N° 5339906 Year: 1978 Material: Stainless Steel Dimensions: 39mm Caliber: Automatic cal. 1520 Crystal: Plexy Bracelet: Nato Accessories: A second bezel for MilSub forniture In the 1970s, the British Ministry of Defence (MOD) commissioned Rolex to create a military-specification watch for its officers. The requirements included fixed spring bars welded to the lugs, preventing the installation of a reflective bracelet, a nylon Nato strap, a 60-minute bezel insert, large sword-shaped hands, and a luminous dial. The MOD also required that the dials be marked with a circled 'T,' indicating the use of luminescent tritium. Furthermore, the casebacks featured military engravings, as seen on the example in question: 0552 for the British Ministry of Defence, 923-7697 for the NATO code, the Broad Arrow that characterizes all watches owned by the British Army, the issue number 829, and the year of issue 78. After decommissioning, these military wristwatches were often destroyed by the British Ministry of Defence or purchased by civilians or dealers, and most were transformed by removing the military features and transforming the watch into a more 'civilian' timepiece. Consequently, finding such an example is an incredible feat, in excellent condition and unrestored. This watch displays all the original features except for the bezel, in this case a standard 15-minute bezel from the reference 5513 and accompanied by a forniture second 60-minute bezel.