Engineered for the Deep The Sea-Dweller is a professional dive watch created for saturation divers working at great depths. With its helium escape valve and robust construction, it is built to perform in the most demanding underwater environments. Classic Tool Watch This 1999 Rolex Certified Pre-Owned Sea-Dweller, reference 16600, features a black dial, rotatable bezel and a 40mm Oystersteel case. The Fliplock Oysterlock clasp ensures a secure fit, while the calibre 3135 movement delivers a 48-hour power reserve.