Designed as a tool for professional divers, the Sea-Dweller was officially launched in 1971, as one of the most reliable and robust diver's watches on the market. Water resistant to 610 meters, its capabilities exceeded that of the Submariner of almost three times.Excluding the very first examples, or prototypes, that displayed a single red Sea-Dweller script, the early specimens of the reference proudly showed the writing "Sea Dweller Submariner 2000" in two red lines, earning their nickname "Double Red Sea-Dweller".The highly coveted “Double Red” lines were ceased in 1977, and subsequently replaced by models featuring white writing on the dial, until the end of the reference’s production in 1981.