The acronym ‘GMT’, or Greenwich Mean Time, the benchmark meridian time, refers in watchmaking terminology to a (dual or) second time zone indicator. Driven by a spirit of research, Robert Greubel and Stephen Forsey have gone well beyond this conventional time zone display using a window or a hand, by incorporating into their timepiece a terrestrial globe completing each anti-clockwise rotation in 24h - the same direction in which our planet spins.
Naturally, and in this too we can recognize the "Greubel Forsey signature", the utmost care is taken with the decoration of the components, down to the smallest details. The hand finishes take in the entire range of traditional techniques, from frosting to hand-bevelling, as well as the subtleties of hand-polishing, lapping, and straight graining with flat black polished finishes. The domed crystal, the case-back and lateral window are made from sapphire crystal. The hand- stitched black alligator strap has a platinum folding clasp. A magnificent demonstration of expertise harnessed for the pursuit of fine craftsmanship.
The GMT calibre is powered by two barrels providing a 72-h power reserve with a frequency of 21,600 vibrations/hour. The calibre comprises 443 components. It features a 24-second tourbillon with 25° inclination, comprising 87 components for a total weight of 0.36 g.
Besides its chronometric properties and reliability, this regulator system was adopted for its small size, which meant that a calibre diameter of 36.40 mm (16 ½ lines) could be kept. This makes for a new medium-sized case, 43.5 mm wide with a total height of 16.14 mm.
Made from 950 platinum, it has a slightly lighter hue than the previous white gold version.