In the category of indestructible solidity, this special edition from Germany's Sinn scores high marks. The U1 DS is a diving watch that is verified and certified to a diving depth of as much as 1,000 metres.
SALTWATER-RESISTANT
You will never have to test that, but it is a comforting thought when you are wearing the watch while snorkelling. Something that does benefit you directly is the metal used to build this watch: it is a special type of steel developed by Thyssen-Krupp for the outer casings of the German Navy's latest non-nuclear submarines, the 212 class.
This is exceptionally strong and has superior anti-magnetic properties. Its mechanical strength is more than 1.55 times that of the usual AISI 316L steel for watch cases. Another advantage is its unique saltwater resistance. Normally, a watch case must be rinsed in fresh water after contact with salt water, otherwise corrosion may occur. Submarine steel is completely resistant to long-term contact with salt water. On top of these advantages, Sinn places another: the surface of the case, crown and -if applicable- strap are hardened with TEGIMENT Technology. This method is not based on applying a coating, but is a special process in which a protective layer (tegimentum in Latin) is created, offering significantly better protection against scratches than the base material does. So count on a scratch-free watch for many years.... Except where the dial is concerned. On this special edition, it has actually been subtly scratched by hand for a decorative effect, which also makes each watch unique. The watch features a solid automatic Sellita SW 200-1 movement. The edition is 500 pieces. Costs from €2,200. www.sinn.de
English 
Dutch 
German