Photo by Greubel Forsey (CC BY 3.0), via Wikimedia Commons · stand-in: Greubel Forsey Quadruple Tourbillon à Différentiel, same Greubel Forsey tourbillon family as the Balancier Convexe; Balancier Convexe exact model not on Wikimedia Commons.
Balancier
Greubel Forsey’s "balance-wheel" branch: pieces built around oversized variable-inertia balance wheels visible through dial-side apertures, rather than the inclined tourbillons that anchor the rest of the catalog. The Balancier Convexe S² (titanium, integrated rubber strap, 2021) carries the family into the sport-cased territory the GMT Sport opened up. The Double Balancier carries two coupled balances on the same architecture.
