New material, new colours, new finishes for this limited edition of the GMT Quadruple Tourbillon by Greubel Forsey, a watch that is non-conformist in every respect, first and foremost its construction. With the Quadruple Tourbillon, Greubel Forsey's second fundamental invention, the aim is to achieve the goal of nullifying the rate deviations due to the force of the Earth's gravity in all the positions assumed by the watch, especially in stabilised positions. To achieve this, the original tourbillon underwent several modifications: first, it was inclined by 30°, then it was doubled and finally quadrupled. The result is two synchronised double tourbillons, in which a first cage inclined at 30° makes one rotation in one minute, inserted into a second flat cage that makes one rotation in 4 minutes. A spherical differential connected to each of the four tourbillons transmits the running average, significantly improving the chronometric performance of the whole. In addition, the new GMT Quadruple Tourbillon proves to be a non-conformist watch on many fronts, including aesthetics. With this exclusive blue titanium version, the House offers a novel alternative to the noble metals traditionally proposed by Haute Horlogerie. Titanium offers several advantages: lighter and at the same time more resistant than steel, it is characterised by its insensitivity to corrosion and magnetic fields. The high hardness of titanium, which characterises the 46.5 mm case of the GMT Quadruple Tourbillon, poses great challenges in the manufacture and finishing of components such as the GMT button, the folding clasp and the crown. New finishes have been specially developed for this model, such as the circled, bevelled and polished hour circle, proposed for the first time in blue. The plate is proposed in grey with a grené finish, as are the bridges, bevelled and with finished flanks. This blue variant casts a new light on the globe at 8 o'clock. An original creation by Greubel Forsey launched exactly ten years ago (in 2011), the globe enables several time zones to be displayed simultaneously: on the dial side, with the 24-hour display surrounding the constantly rotating globe; on the caseback side, with a disc depicting the 24 reference cities of the different time zones. The disc also makes it possible to distinguish the cities that apply daylight saving time (in light) from those that do not (in dark). A sapphire crystal window completes the ensemble: positioned at the equator, it offers a complete view of the Earth in motion, whose continents appear surrounded by blue ocean masses, a hue that echoes the new blue finish of the hour circle, the power reserve and the strap.
