The GMT Quadruple Tourbillon had only one chapter. Today, Greubel Forsey writes the second and reveals an 11 piece edition of this groundbreaking timepiece in Titanium. With new materials, new colours and new finishes, this revolutionary and modern limited edition launches the GMT Quadruple Tourbillon towards unexplored horizons and resolutely marks the dawn of a new chapter.

The GMT Quadruple Tourbillon is radical in all its aspects. First of all, by its construction. The Quadruple Tourbillon is Greubel Forsey’s second Fundamental Invention, The mission: to average out positional errors due to gravity in all situations, especially in stable wristwatch positions.

To achieve this, the original tourbillon has been elevated to realise its full potential: inclined at 30°, doubled and then quadrupled. The result, two synchronised Double Tourbillon 30° mechanisms, where a first cage, inclined at 30° and rotating in one minute, is nested within a second horizontal cage, completing a full rotation in four minutes. A spherical differential transmits the average timing rate of the four tourbillon cages, improving the overall chronometric performance of all the regulating organs.

The GMT Quadruple Tourbillon is radical by design. With this exclusive limited edition in titanium with striking blue accents, Greubel Forsey offers an unexpected alternative to the precious metals that High-end watchmaking traditionally favours. Titanium has numerous qualities: it is both stronger and lighter than steel, while also being extremely resistant to corrosion and magnetic fields.

With a reduction of over a third of its weight, the new titanium case offers a brand new, modern and dynamic feel on the wrist, which has inspired the choice of the new rubber strap, in order to assert this new contemporary identity.

The toughness of titanium, which defines the 46.5 mm case of the GMT Quadruple Tourbillon, presents a significant machining and hand finishing challenge for the components made from it, such as the GMT pusher or the folding clasp or the crown. In addition, new hand finishing details have been specially created for this timepiece. The circular-grained hour ring with polished bevels and 72-hour chronometric power reserve indication appear for the first time in a brilliant blue. The mainplate is now frosted and spotted with polished bevelling, countersinks and straight-grained flanks, executed in a grey finish.

Planet Earth, set near eight o’clock, shines in a new light with the blue livery. An original Greubel Forsey creation from ten years ago (2011), the rotating terrestrial globe allows for the simultaneous display of several different time zones: on the dial side, with a 24-hour ring around the Earth, for Day/Night indication and on the case-back side, displaying 24 major cities their respective time zones while distinguishing between those which use summer time (on a light coloured backdrop), and those which do not (on a dark backdrop).

The sapphire crystal window around the equator completes the timepiece, offering a complete view of the Earth in motion, with its continents immersed in the deep blue ocean waters, complementing the exquisite blue finish of the power reserve, hour circle and strap.

Mouvement	:	GMT Quadruple Tourbillon 11 pieces in titanium Hand-wound movement with 3 patents GMT 2nd time zone Rotating globe with universal time and day-and-night Universal time on 24 time zones Cities observing summer time Lateral window showing the equator and southern hemisphere GMT pusher Quadruple Tourbillon Hours and minutes Small seconds Power-reserve
Diameter	:	39.50 mm
Thickness	:	13.00 mm
Number of parts	:	Movement : 705 parts Four tourbillon cages: 260 parts Total weight of the cages: 2.25 g Spherical differential: 28 parts
Jewels	:	84 Olived-domed jewels in gold chatons
Chronometric power reserve	:	72 hours
Barrels	:	Three series-coupled fast-rotating barrels(1 turn in 3.2 hours), one of which is equipped with a slipping spring to avoid excess tensions
Balance wheel	:	Variable-inertia with white gold mean-time screws (10.70 mm diameter)
Frequency	:	21’600 vibrations / hour
Balance spring	:	Phillips terminal curve Geneva-style stud
Main plates	:	Nickel silver, frosted and spotted with polished bevelling and countersinks, straight-grained flanks, grey treatment
Bridges	:	Nickel silver, frosted and spotted, polished bevelling and countersinks, straight-grained flanks, grey treatment Gold plate engraved with the individual number Flat black polished gold plates with relief-engraved text, polishedbevelling and countersinks,straight-grained flanks Four flat black polished steel tourbillon bridges, hand-polished bevelling and countersinks, straight-grained flanks
Inner tourbillons	:	Inclined at a 30° angle 1 rotation per minute
Outer tourbillons	:	1 rotation in 4 minutes Hand-bevelled and openworked cage pillars 1 gold counterweight per double cage bearing the individual number of the timepiece
Gearing	:	Involute circle profile Conical gearing with profiled teeth
Displays	:	Hours and minutes Small seconds (mean performance) 72-hours power reserve on a sector 2nd time zone GMT 24 time zones universal time Rotating titanium globe with universal time Cities observing summer time Day-and-night
Case	:	Titanium with asymmetrical convex synthetic sapphire crystal n Transparent back with asymmetrical convex synthetic sapphire crystal Lateral window with shaped synthetic sapphire crystal Three-dimensional, variable geometry-shaped lugs Raised polished engraving “GMT Quadruple” and “Greubel Forsey” on a hand-punched background Gold security screws Polished bezel, caseband with hand-finished straight graining Titanium GMT pusher with raised engraving on a hand-punched background Engraved individual number
Diameter	:	46.50 mm
Height	:	17.45 mm
Water resistance	:	3 atm - 30 m - 100 ft (standard NIHS 92-20/SN ISO 22810:2010)
Crown	:	Titanium with engraved GF logo
Dial	:	Multi-level in gold, anthracite colour Gold hour-ring and power reserve, circular-grained with polished bevelling, blue treatment Gold hour markers GMT in gold, hand matt lapped Small second, circular-grained
Hands	:	Hours and minutes in polished gold, with Super-LumiNova Small seconds in polished steel, black treatment Power-reserve in polished steel, hand-polishedcountersink 2nd time zone GMT indicator, red
Bracelet	:	Rubber or hand-sewn alligator
Buckle	:	Titanium folding clasp, engraved with the GF logo