niversal time is read from the globe itself rather than from a hand. Around it, the dial is built as an amphitheatre, with hours, minutes, small seconds, second time zone, day and night and 72-hour power reserve each on its own level.

Where its predecessor kept its power reserve to itself, this generation displays it on the dial. The calibre was re-engineered around it, growing by 73 components to 496 while improving its chronometric performance. The inclined escapement remains suspended beneath a flat black polished and barrel polished steel bridge, resting on polished steel pillars.

On the reverse, a sapphire disc engraved with 24 reference cities allows universal time to be read against every zone, with a second scale for summer and winter time. La Chaux-de-Fonds has replaced Paris. A GMT built here should keep its own meridian.

The Convexe case, sculpted in titanium at 42.9 mm, curves front and back so that the timepiece sits lower than its dimensions suggest. Titanium keeps it light, the strap keeps it in place, and the blue inserts in the crown mean the one part you handle daily belongs to the whole.

The latest and only GMT in the current collection, built in a limited series of 22 timepieces.

TECHNICAL SPECIFICATIONS

GMT Balancier Convexe In titanium Limited edition Patented hand-wound movement

MOVEMENT MOVEMENT DIMENSIONS

• Overall diameter: 37.80mm
• Thickness: 13.80mm

NUMBER OF PARTS

• Movement: 496 parts
• Escapement platform: 59 parts

NUMBER OF JEWELS

• 72
• Olived-domed jewels in gold chatons

CHRONOMETRIC POWER RESERVE

• 72 hours

BARRELS

• Two series-coupled fast-rotating barrels (1 turn in 3.2 hours), one of which is equipped with a slipping spring to avoid excess tension

BALANCE WHEEL

• • In-house variable-inertia with 6 gold mean-time screws (12.60mm diameter)

FREQUENCY

• 21’600 vibrations/hour

BALANCE SPRING

• Phillips terminal curve
• Geneva-style stud

BRIDGES AND MAIN PLATES

• Titanium and nickel-silver
• Frosted, polished bevelling and countersinks, straight-grained flanks
• Power reserve and small seconds bridges with blue treatment

ESCAPEMENT PLATFORM

• Inclined at a 30° angle
• Flat black polished steel, polished bevelling and countersinks, straight-grained flanks
• Polished steel pillars
• Flat black polished and barrel polished steel balance wheel bridge

GEARING

• Involute circle profile
• Inclined gear with profiled teeth on fourth wheel

DISPLAYS

• Hours and minutes
• Small seconds
• 2nd time zone GMT
• Rotating globe with universal time
• Day-and-night
• 24 time zones universal time
• Summer time, winter time
• 72-hours power reserve on a sector

EXTERIOR CASE

• Titanium with curved sapphire crystal
• Three-dimensional, variable geometry-shaped bezel, hand-polished with hand-finished straight graining
• Profiled lugs, screwed fixin
• Transparent back with curved and high domed synthetic sapphire crystal
• Engraved GMT pusher
• Titanium security screws
• Raised engraving “GMT” and “Greubel Forsey”

CASE DIMENSIONS

• Caseband diameter: 42.90mm
• Bezel diameter: 44.90mm
• Case height: 15.10mm
• Height on synthetic sapphire crystals: 17.60mm

WATER RESISTANCE OF THE CASE

• Water-resistant 5atm - 50m – 164ft (standard NIHS 92-20/SN ISO 22810:2010)

CROWN

• Titanium and rubber with GF logo
• Colour-coded rubber capping, interchangeable

DIAL SIDE

• Terrestrial globe in titanium, relief-engraved continents, ocean blue treatment
• Day-and-night UTC indicator in titanium, engraved and lacquered
• GMT indicator in gold
• Amphitheatre hour-ring with engraved and lacquered minute-circle
• Small seconds indicator in gold

MOVEMENT SIDE

• Synthetic sapphire disc displaying city names surrounded by 2 rings (UTC and summer time) engraved and lacquered, hand matt lapped
• Gold “summer time” plate with limitation number, raised engraving, hand matt lapped

HANDS

• Hours and minutes, red triangles with Super-LumiNova
• 2nd time zone GMT indicator, red triangle
• Small seconds in polished blued steel, flat black polished head

STRAP AND CLASP • Hand-sewn textured rubber or rubber with text in relief • Titanium folding clasp, engraved GF logo • On demand: 3-row metal bracelet in titanium, folding clasp with integrated fine adjustment, engraved GF logo