Description: Rolex Sea-Dweller 16600 Pre-owned Rolex Sea-Dweller ref 16600 (1999). Rolex released this variation of the SD in the late 1980s and kept it in production until around 2009. It replaced the previous ref. 16660 (Rolex Triple Six), featuring the same depth rating and sapphire crystal, but with the caliber 3135, an upgrade over the previous caliber 3035. With its steel and black design, white gold hour markers, and 40mm case, many have noticed the watch’s similarities