Nano Foudroyante is a luxury Wristwatch by Greubel Forsey.

In October 2025, Greubel Forsey presented the first official limited edition of its Nano Foudroyante: a groundbreaking timepiece that is the result of years of research and has now matured beyond its origins in Experimental Watch Technology (EWT).

At the heart of this timepiece lies a disruptive idea: nanomechanics – the control of energy at the nanojoule scale inside a mechanical movement. This paradigm shift enables the Nano Foudroyante to operate its eponymous complication using just 16 nanojoules per jump, compared to 30 microjoules in traditional designs – a reduction by a factor of 1,800.

The complication divides each second into six segments using a lightweight, red-treated hand that rotates once per second, driven directly by the oscillations of the 3 Hz balance wheel. There is no traditional gear train; instead, a minimalist series of low-inertia wheels efficiently distributes energy through the movement.

The timepiece features a hand-wound flyback with 2 patents, totaling 428 components (including 142 for the tourbillon cage). Despite this complexity, the movement measures just 31.60 mm in diameter and fits within a 37.90 mm white gold case – Greubel Forsey’s most compact ever.

With this model, Greubel Forsey wins the ‘Mechanical Exception Watch Prize’ at the Grand Prix d'Horlogerie de Genève 2025.