The Greubel Forsey Convexe family takes its name from the characteristic convex shape of the case that curves to meet the shape of the wrist. The bezel and crystal too are similarly curved in shape to provide an expansive view of the dial.

The Balancier Convexe S² was the brand’s first timepiece to feature a carbon composite case when it debuted in 2023. Carbon composite cases in watchmaking is not new, but the construction of the Convexe S² was anything but simple. Due to the unique curved shaped of the case, 16 tonnes of pressure per square centimetre was required to bind the stacks of carbon fibre sheets and resin together.

This pressure is eight times higher than what is typically employed for traditionally shaped carbon cases. The case’s durability is enhanced by employing multiple layers of carbon, each just 1 to 5 microns thick, resulting in a compact and precisely shaped case. The fibres are aligned to follow the curvature of the Convexe case.

The mainplate and main bridge of the movement are also made from carbon composite and this black background really serves to highlight the highly polished titanium and steel components of the movement. The movement still features the brand's now trademark inclined balance wheel that promises more chronometric efficiency. The balance wheel sits at a 30˚ incline to the horizonal plane of the watch.

A limited edition of just 22 pieces, the Convexe S² will appeal to those who’ve always admired the technical virtuosity of Greubel Forsey from afar, but have intimidated by the larger case sizes that have been associated with the brand. Though the Convexe S² case has a base diameter of just 41.5 mm (44 mm across the bezel) and is only 12.85 mm. thick, it wears smaller thanks to the curvature of the case and black-colour scheme.