In the 1960s professional marine divers were in search of the perfect watch for helping to keep safe in 1,000 feet deep water. Rolex put on their thinking caps and worked to develop a watch that would exceed their needs. In 1967, the company released the Rolex Oyster Perpetual Sea-Dweller Submariner 2000.The watch can be used at depths of up to 2000 feet! To accomplish this feat, Rolex had to increase the thickness of the crystal to protect the watch face. Rolex Sea-Dweller 4000, with an increased depth rating to 1,220 metres (4,000 ft). The last Comex Sea-Dweller 4000 Rolex reference number is 16600. Rolex introduced an updated Sea-Dweller model named the Rolex Sea-Dweller DEEPSEA. Its reference number is 116660. With an official depth rating of 3,900 metres (12,800 ft), the Sea-Dweller DEEPSEA represented in its launch year the most water resistant mechanical watch in serial production. Rolex Deepsea D Blue Dial 116660 was put on the submersible with James Cameron. Replica Rolex Sea-Dweller Watches: