Source: Images and content by Rolex. See the original article here - https://newsroom.rolex.com/watches/oyster-collection/gmt-master-ii
ROTATABLE BEZEL AND ALTERNATIVE TIME ZONE
The time in an alternative time zone can be displayed by simply turning the rotatable bezel. In this case, the reference time is no longer shown, as it is the alternative time zone that is now read via the 24-hour hand against the graduations on the bezel.
The bezel was carefully designed to ideally fulfil its function. Rolex developed a bezel rotation system with a trigonal spring that allows the bezel to be turned crisply and securely in either direction and locate with a positive click in each of the 24 different hour positions. The bezel can be turned with ease thanks to its knurled edge, which offers excellent grip.
BEZEL WITH CERACHROM INSERT
The bidirectional rotatable bezel of the GMT-Master II is equipped with a 24-hour graduated, two-colour monobloc Cerachrom insert. The insert, patented by Rolex, is made of extremely hard, virtually scratchproof ceramics whose colours are unaffected by ultraviolet rays. In addition, thanks to its chemical composition, the high-tech ceramic is inert and cannot corrode. The moulded, recessed graduations and numerals are coated with gold or platinum using a PVD (Physical Vapour Deposition) process. Over and above its functions and its intrinsic technical assets, the GMT-Master II bezel contributes to the model’s strong visual identity.
In 2013, Rolex broke new ground when it introduced its first single-piece, two-colour ceramic bezel insert – blue on one half and black on the other – on an Oystersteel version of the GMT-Master II. A year later, it unveiled the two-colour bezel insert in red and blue ceramic, on a GMT-Master II in 18 ct white gold. In 2018, the brand presented its latest innovation, a two-colour bezel insert in brown and black ceramic, on two variants of the GMT-Master II – one in 18 ct Everose gold and the other in an Everose Rolesor version (combining Oystersteel and Everose gold). These Cerachrom inserts blend the technical performance of high-technology ceramic with the iconic aesthetics of the original GMT-Master.
THE GMT-MASTER II, SUPERLATIVE CHRONOMETER CERTIFIED
Like all Rolex watches, the GMT-Master II is covered by the Superlative Chronometer certification redefined by Rolex in 2015. This exclusive designation testifies that every watch leaving the brand’s workshops has successfully undergone a series of tests conducted by Rolex in its own laboratories and according to its own criteria. These certification tests apply to the fully assembled watch, after casing the movement, guaranteeing superlative performance on the wrist in terms of precision, power reserve, waterproofness and self-winding. The Superlative Chronometer status is symbolized by the green seal that comes with every Rolex watch and is coupled with an international five-year guarantee.
The precision of every movement – officially certified as a chronometer by the Swiss Official Chronometer Testing Institute (COSC) – is tested a second time by Rolex after being cased, to ensure that it meets criteria that are far stricter than those of the official certification. The precision of a Rolex Superlative Chronometer is of the order of −2/+2 seconds per day – the rate deviation tolerated by the brand for a finished watch is significantly smaller than that accepted by COSC for official certification of the movement alone.
The Superlative Chronometer certification testing is carried out after casing using state-of-the-art equipment specially developed by Rolex and according to an exclusive methodology that simulates the conditions in which a watch is actually worn and more closely represents real-life experience. The entirely automated series of tests also checks the waterproofness, the self-winding capacity and the power reserve of 100 per cent of Rolex watches. These tests systematically complement the qualification testing during development and production, in order to ensure the watches’ reliability, robustness, and resistance to magnetic fields and shocks.
THE OYSTER CASE, SYMBOL OF WATERPROOFNESS
The GMT-Master II’s Oyster case, 40 mm in diameter and guaranteed waterproof to a depth of 100 metres (330 feet), is a paragon of robustness and reliability. The middle case is crafted from a solid block of Oystersteel, a particularly corrosion-resistant alloy, or from 18 ct gold. The case back, edged with fine fluting, is hermetically screwed down with a special tool that allows only certified Rolex watchmakers to access the movement. The Triplock winding crown, fitted with a triple waterproofness system and protected by an integral crown guard, screws down securely against the case. The crystal, with a Cyclops lens at 3 o’clock for easy reading of the date, is made of virtually scratchproof sapphire. The waterproof Oyster case provides optimum protection for the GMT-Master II’s movement.
PERPETUAL CALIBRE 3285
The GMT-Master II is equipped with calibre 3285, a self-winding mechanical movement entirely developed and manufactured by Rolex. A consummate demonstration of technology, this movement carries a number of patents. It offers outstanding performance in terms of precision, power reserve, resistance to shocks and magnetic fields, convenience and reliability.
The oscillator of calibre 3285 has a large balance wheel with variable inertia regulated extremely precisely via gold Microstella nuts. It is held firmly in place by a height-adjustable traversing bridge enabling very stable positioning to increase shock resistance. The oscillator is also fitted on high-performance Paraflex shock absorbers, designed and patented by Rolex.
Calibre 3285 has an optimized version of the blue Parachrom hairspring, manufactured by Rolex in a paramagnetic alloy. Insensitive to magnetic fields, the Parachrom hairspring offers great stability in the face of temperature variations and remains up to 10 times more precise than a traditional hairspring in case of shocks. It is equipped with a Rolex overcoil, ensuring its regularity in any position.
This calibre incorporates the Chronergy escapement, made of nickel-phosphorus and patented by Rolex, which combines high energy efficiency with great dependability and is also insensitive to magnetic fields.
Calibre 3285 is fitted with a self-winding module featuring a Perpetual rotor, which ensures continuous winding of the mainspring by harnessing the movements of the wrist to provide a constant source of energy. Thanks to its barrel architecture and the escapement’s superior efficiency, the power reserve of this movement extends to approximately 70 hours.
The GMT-Master II’s movement will be seen only by certified Rolex watchmakers, yet it is beautifully finished and decorated in keeping with the brand’s uncompromising quality standards.
BRACELET AND CLASP: SECURE AND COMFORTABLE
The GMT-Master II is available on a three-piece link Oyster bracelet or, for versions in Oystersteel only, on a five-piece link Jubilee bracelet. A concealed attachment system ensures seamless visual continuity between the bracelet and case.
These bracelets are equipped with a Rolex-designed and -patented Oysterlock safety clasp that prevents accidental opening. They are additionally fitted with the Easylink comfort extension link, developed by the brand, which allows the wearer to easily increase the bracelet length by approximately 5 mm, providing additional comfort in any circumstance.
On the 18 ct gold versions of the GMT-Master II, the Oyster bracelet includes ceramic inserts inside the links to enhance its flexibility and longevity.
