The Sea-Dweller is one of the most robust Rolex watches. The Genevan company first released this timepiece in 1967 as an evolution of the Submariner, which had debuted 14 years prior. Unlike its close relative, however, the Sea-Dweller can dive to 1,220 m (122 bar, 4,000 ft) and is suitable for professional saturation diving thanks to its helium escape valve. The Sea-Dweller Deepsea is even more impressive. It is water-resistant to 3,900 m (390 bar, 12,795 ft) and, at 44 mm, is one of the largest models in Rolex's portfolio.