The Rolex Military Submariner reference 5517, known as the “MilSub”, was made around 1977 for the British Ministry of Defence. It has a 40 mm stainless steel Oyster case, a rotating bezel and a black dial without a date, and it runs the automatic calibre 1520. It differs from the civilian 5513 in its sword-shaped hands, a bezel with a 60-minute scale and fixed spring bars drilled through the lugs, so a NATO-style strap can be used.

Rolex supplied the watches to the British forces, and the casebacks are engraved with Ministry of Defence markings. Output is usually given as roughly 1,300 pieces, although I could not confirm that figure from an official source, and the watches were issued from 1976 and 1977.

The MilSub is among the most prized Rolex references, and the community values it for its provenance as much as its looks, with documented examples reaching very high prices at auction. It was a limited military order and is long out of production.