Rolex 16660 (Pre-owned - Good) — USD 8,450 on eBay

The Rolex Sea-Dweller reference 16660, often referred to as the "Triple Six," represents a significant transitional model within the Sea-Dweller lineage. It was the first Sea-Dweller to incorporate a sapphire crystal, a crucial upgrade that enhanced its pressure resistance and durability compared to its plexiglass predecessors. This reference also marked the introduction of a larger helium escape valve, further solidifying its professional dive watch credentials and distinguishing it from earlier iterations. It bridges the gap between the vintage four-digit references and the more modern five-digit models. This reference features a 40 mm stainless steel Oyster case, designed for extreme depths. It is powered by the automatic Caliber 3035, a robust movement known for its reliability and quick-set date function. The watch is equipped with a sapphire crystal, contributing to its impressive water resistance of 1220 meters (4000 feet). The unidirectional rotating bezel allows for precise timing of immersion, and the Oyster bracelet ensures secure wear during demanding activities. For collectors, the 16660 is notable for its transitional characteristics, offering both vintage appeal with its matte dial variants in early production and the enhanced technical specifications of later models. It appeals to those seeking a robust tool watch with historical significance, representing a key evolutionary step in Rolex's professional dive watch development. The reference is recognized for its engineering advancements and its role in the continuous refinement of the Sea-Dweller series.