The Porsche Design Bund line of wristwatches holds a place of special importance within the history of the company as it is the last line of watches made specifically for military purposes. It is a "spin off" of the Porsche Design Ocean 2000 line of timepieces launched in the early 1980s - itself a continuation of the collaboration between PD and IWC which had begun in 1978. Concurrently to the launch of the civilian model, IWC obtained a contract from the West Germany Army to realized military versions of the watches. As it often happens in watchmaking, these military pieces had different specs from the civilian models. Most notably, they feature orange seconds hand, black bezel, a flat crystal and a nylon strap (the titanium bracelet was optional). Interestingly, while the civilian version was rated to 2000 meters below sea level (thus its name "Ocean 2000"), the military version was only tested up to 300 m.

Three different models were made for the Navy: a "Kampftaucheruhr" (combat diver) model, bearing ref. 3314 or 3315 introduced in 1983; a "Minentaucheruhr" (minesweeper models) ref. 3519, and the present "Taucheruhr" (diver) model ref. 3509 (and its sibling ref. 3529).

For the Taucheruhr model, an upgraded movement with 22 jewels instead of 21 (the difference lying in jewels replacing rotor bearings) with a frequency of 28'800 half-beats/hour was devised. First examples bear calibre 375, later replaced by its upgraded version cal. 3752. The caseback bears the "BUND" designation along with the stock number, which for ref. 3509 can be either 6645-12-8096 or 6645-12-197-9681.

The present example of this remarkable model is not only offered complete of all its original accessories, but furthermore in absolutely original and unrestored condition, an absolute gem for the collector of scarce and historically relevant timepieces.