Rolex Deepsea watch, polished round stainless steel case (44mm diameter, 15mm thickness) with shoulders to protect the screw-down Triplock winding crown, specially designed helium escape valve and new Ringlock system, lightweight titanium case back, special time-lapse rotatable bezel with scratch-proof Cerachrom insert, stainless steel Oyster bracelet with Glidelock clasp (able to wear over a dive/wetsuit 7mm thick), black dial with luminous hour markers, date calendar at 3 o’clock, 31 jewel caliber 3135 self-winding chronometer movement, slightly domed synthetic sapphire crystal that is thicker than the sapphire crystals of other Oyster models, pressure-proof to 3900 meters (12,800 feet). The Rolex Deepsea is equipped with a Ringlock System, a new case architecture patented by Rolex, which allows the watch to withstand a colossal 2.98 metric tonnes of water pressure. During deep dives lasting several days, the helium molecules spread throughout all the matter and penetrate the watch in sufficient quantity to push out the sapphire crystal at atmospheric pressure levels. The helium escape valve of the Rolex Sea-Dweller Deepsea prevents this from happening. The valve is used by divers to release helium from their watch while they rise up to the water’s surface.