The Rolex Sea-Dweller Ref. 16660, known to collectors as the ‘Triple Six’, occupies a unique space in the Sea-Dweller lineage. Introduced in 1978 as the direct successor to the legendary Ref. 1665, it wasn’t merely an update—it was a leap forward. Still produced alongside the 1665 in its earliest years, the 16660 marked a turning point in Rolex’s deep-sea tool watch development, ushering in a more modern era while quietly retaining the soul of its predecessor.
The changes were meaningful: a sapphire crystal replaced the acrylic of earlier models, and the helium escape valve was enlarged and improved—resulting in a doubled depth rating of 1220 meters (4000 feet). Internally, it introduced the caliber 3035, a faster-beating, quickset movement that replaced the slower 1575 of the 1665.
These advancements made the 16660 the most capable Sea-Dweller to date, but its transitional charm lies in the dial variations seen during its production. Early examples featured matte dials with large tritium plots (‘Palletoni’), bearing no white gold surrounds—a direct visual link to the 1665. By the mid-1980s, however, these were replaced by glossy dials with white gold-trimmed lume plots (‘Bicchierini’), setting the tone for the modern Submariner and Sea-Dweller aesthetic.
It’s this duality—the presence of both vintage design cues and modern innovation—that gives the Triple Six its allure. It lives at a crossroads: still rugged and tool-like, but updated just enough to feel contemporary.
Production of the 16660 ended in 1988, making way for the Ref. 16600. But for many collectors, it’s the Triple Six that captures the spirit of the Sea-Dweller best—the last to remember its roots, and the first to step into the future.
