CASE NUMBER: 05’174, '1 of 1' engraved on the caseback

The GMT Sport Earth was avant-garde indie brand Greubel Forsey’s first sports watch. The watch featured a new ovoid case with integrated lugs and a sporty rubber strap that sits more comfortably on the wrist.

The open-worked dial is a theatre of haute horology with suspended bridges and floating dials in three dimensions. A suspended arch centre bridge holds the gear train that follows the curve of the bridge that drives the hours and minutes hand. An auxiliary dial between 10 and 11 o’clock combines the small seconds on a large rotating disc, and the second time zone display with a hand.

The trademark inclined tourbillon completes a rotation every 24 seconds and is placed at 1 o’ clock. The tourbillon cage alone has 88 components but weighs only 0.38 grams thanks to light alloy pillars and titanium bridges.

A rotating globe as seen from above the North Pole and rotating around its axis in real time. It is surrounded by a sapphire crystal ring with 24-hour divisions; where the wearer can read local time for all longitudes, including the day / night indicator (light zone / dark zone). The caseback features a sapphire cities disc to give UTC Universal and Summer Time for 24 cities in major time zones.

While earlier GMT Sport Earth models, the bezel of the present one-off timepiece opts for a horizonal satin-brushed finish instead of the engraved text that was seen on earlier models. Also this timepiece offers a unique all-green colour scheme – the mainplate, globe, 24-second ring at the second time zone dial are all in the same green hue. It’s rarity unique colour scheme is highlighted by the ‘1 of 1’ engraving on the caseback and confirmed by the Certificate of Authenticity.