Fortis offers not only great instruments for staying in the clouds, but also for underwater action. The tradition of waterproof Fortis watches dates back to 1940. The then introduced "Fortissimo" was one of the first waterproof watches in the world. In 1952, a series of Marinemaster was established, which can be found in the offer of Fortis to this day. It is interesting that the right to use the name "Marinemaster" shares Fortis with the Japanese giant Seiko, which also offers a diver of the same name. It is not clear which brand this name first.