The Rolex Oyster Perpetual Sea-Dweller Submariner 2000 (2000 ft = 610 m) that became available in 1967 was developed from the Submariner for the Comex S.A. industrial deep-sea diving company by increasing crystal thickness and was produced in several variations. It had a depth rating of 610 metres (2,000 ft) and its Rolex reference number was 1665.
Most Sea-Dweller watches incorporate a helium escape valve for saturation diving. Early Sea-Dwellers did not always have the helium escape valve. The model is also distinguished by the absence of the date magnifier ("cyclops") present on most other Rolex models. The Sea-Dweller diving watch range has been standard issue for Comex divers since 1977.
The Sea-Dweller Submariner 2000 watches had 2 red text lines on the watch dial which led to an unofficial "Double Red" designation under watch collectors for these watches.
Rolex Sea-Dweller 4000 with a 1,220 m (4,000 ft) depth rating.
The Sea-Dweller Submariner 2000 models were succeeded by the Rolex Oyster Perpetual Sea-Dweller 4000 (4000 ft = 1220 m) model with an increased depth rating to 1,220 metres (4,000 ft). The last Comex Sea-Dweller 4000 Rolex reference number is 16600 and this watch was issued to Comex divers since 1992.
Several semi custom production runs of Sea-Dweller Submariner 2000 and 4000 models were produced with and without helium escape valves and differing watch dial patterns for the Comex S.A. company. These variants sometimes also had differing Rolex reference numbers. Some of these non standard Sea-Dweller watches had the Comex S.A. logo depicted on the watch dail which led to an unofficial "COMEX watches" designation under watch collectors for these watches. These watches were either issued to actual Comex staff members or served as gifts for business relations.
