In the 1970s the British Ministry of Defense commissioned Rolex for a watch with specific military specifications to be worn by its officers. These requirements included fixed spring bars welded to the lugs which prevented the fitting of a reflective bracelet, a nylon strap (by contract from the Phoenix company), a 60-minute bezel insert, large sword-shaped hands, and a luminous dial. In addition, the MOD required that dials be marked with an encircled “T” indicating the use of luminescent tritium. Rolex used its Submariner reference 5513 as a base and as such the military version of the Submariner or “MilSub” was born.

Additionally, the casebacks for watches issued to the British Army were engraved with “W10”, the code for the British Royal Army, and “6645-99-9237697”, the NATO codes, followed by the issue number. The original owner of the present watch, upon parting with his watch and worried that the numbers on the caseback would put him in trouble with the MOD, had these numbers polished out. However, what this watch lacks in engravings on the caseback it makes up with its superb condition, the case maintains its original proportions, tick lugs with crisp bevels, perfectly crisp serial and reference numbers engraved between the lugs. The dial is devoid of any major flaws and the serial number is correctly engraved inside the caseback.

Since it was issued, the watch has had three owners and been serviced once, as attested by the single London service mark inside the caseback. The watch is also delivered with its service invoice, credit card receipt and Rolex Service Guarantee dated 11 April 2014.