Sea-Dweller Triple Six 16660

The first sapphire-crystal Sea-Dweller, with a thicker case, a larger gas escape valve and a unidirectional bezelBezelThe frame surrounding the crystal at the front of a watch., doubling the rating to 4,000 ft / 1,220 m. Quickset dateQuickset dateA setting function that adjusts the date directly through a crown position, without repeatedly advancing the hands through full days. via cal. 3035; the date disc turned off-white from silver. Made alongside the 1665 until 1983. Early casebacks read “Rolex Patent”, later ones “Rolex Oyster Original Gas Escape Valve”.