Seiko Swedish Navy 6105-8110
This is a "Holy Grail" for Seiko collectors and military collectors: the Seiko 6105-8110 with "Tre Kronor" or "Three Crowns" engraving on the case back and issued to the Swedish Navy. Only a few examples are known. On one forum, a gentleman says they were used by a mine diver unit and coast artillery units.
I purchased it earlier this year at auction from Bukowski's in Stockholm, Sweden for about $4,300 taking fees into account. I was honestly willing to go much higher as the watch really is extremely special to me and I am not sure if I will ever have the opportunity to own another one.
You can read more about them here: