Professional Diver The Sea-Dweller was created for the most demanding underwater environments, a professional-grade instrument that has earned its place in the history of deep-sea exploration. This 40mm model reflects that tradition, combining strength with uncompromising accuracy. Its Oystersteel case and black dial underscore its commanding presence. Technical Assurance Powered by the calibre 3135 with a 48-hour power reserve, this reference features a rotatable 60-minute bezel and Fliplock clasp for security. The sapphire crystal ensures durability and performance.