A nickname given to saturation divers living for weeks in pressurized underwater habitats. The ultra-resistant divers’ model engineered by Rolex in 1967 as the reliable tool for the conquest of the deep. Originally waterproof to 2,000 feet (610 meters), then to 4,000 feet (1,220 meters) in 1978. Introduced the Rolex-patented helium escape valve, a decompression device for the watch during deep saturation diving.