Watch of the day: Rolex Submariner

• Is waterproof to a maximum depth of 300 metres/1000 ft.

• Has the Triplock system, featuring a triple gasket system, is identified by three dots on the crown which screws down tightly onto the case tube and against the Oyster case providing another layer of protection.

• Has a case made from a solid block of 904L stainless steel or gold. 904L steel is a corrosion-resistant stainless steel alloy. Rolex makes its gold in its own foundry where it can create new alloys and control the quality of the gold.

• As what many professional divers consider to be a "true" diving watch, among many, the Submariner utilizes a unidirectional bezel that enables the diver to memorize and follow immersion time. Since the bezel only rotates counterclockwise, the dive time can only become "shorter" in case of accidental bezel movement, thus avoiding the danger of spending too much time underwater.

• Has the Perpetual rotor in the self-winding wristwatch mechanism which allows the watch to run continuously because every slight movement of the wrist winds the movement and the energy generated is stored in the mainspring which can allow the watch to continue to function with no movement for up to two or three days. Every movement is an officially certified Swiss chronometer by the COSC. At midnight the Rolex calendar mechanism advances to the next date in a single short rotation.

• As of summer of 2007 the 14060M non date version became a COSC certified Swiss chronometer.

• As of 2007, and more particularly, with the "Z" serial number series, there are no holograms on the casebacks.

• A new submariner, model 116613 (not to be confused with model 16613) based on the "supercase" used in the GMT II was presented at the 2008 Basel show. The first Submariner models offered are a yellow gold with blue face and bezel and a new white gold with blue face and bezel. The stainless steel case model was presented at the 2010 Basel show. It's reference is 116610.

• Recent models of the Submariner (late 2008) have a distinctive "ROLEX ROLEX ROLEX" and serial number engraved on the "inner bezel" also known as the "Rehaut" (French) or "Flange" (English).

• The no-date Submariner is marginally thinner, and has a thinner bezel than its date-sporting contemporary. It is also much rarer than the date model Submariner because dealers typically order the nominally more expensive 'date' version.