Consigned by the original owner, the present timepiece is a reference 5513/17, displaying '5513' between the lugs and '5517' beneath the lug. It represents the rarest iteration among the three MilSub references. Furthermore, the outside caseback bears an engraving with the following markings:

0552 for the British Ministry of Defence, 923-7697 for the NATO code (North Atlantic Treaty Organization), the Broad Arrow symbol identifying all watches owned by the British Army, the issue number 669 and the issue year 77.

This timepiece was issued to Captain Andrew Elvin OBE, a British Royal Navy Deep Specialist Mine Warfare and Clearance Diving Officer, in 1989. A 35-year veteran of numerous global operations, conflicts, staff appointments, and 12 years working closely with the United States Navy, he was appointed an Officer of the Military Division of the Most Excellent Order of the British Empire (OBE) by Her Majesty Queen Elizabeth II for his outstanding service as Deputy Commander of Task Force 52 of the United States Mine Warfare Force in the Middle East in 2013. More recently, he is a United States Department of Defense Contractor, an independent consultant and also dives in support of the Rhode Island Marine Archeology Project on the United States Revolutionary War wrecks (including Captain Cook’s HMS Endeavour).

Reference 5513
The Military version of the Submariner ref. 5513 was adapted following the specifications request by the British Ministry of Defence. These modifications included easily readable dials with large 'sword' hands and fixed bar lugs with a minimum diameter of 2 mm. to guarantee the safe fastening of a NATO strap. The encircled 'T' symbol, which indicates the use of tritium for luminescence, was also displayed on each dial. The hack feature, which enables exact time synchronization, was another prerequisite. Instead of the typical 15-minute demarcation, the bezel was specially set up with a full 60-minute scale. Unusually, the serial number of the watch was also engraved on the inside of the case backs, a feature usually only present between the lugs on civilian models.