Greubel Forsey Double Tourbillon 30°

Greubel Forsey's first fundamental invention, featuring a 30° inclined inner tourbillon rotating once per minute inside an outer tourbillon cage rotating in four minutes. This configuration averages out gravitational errors affecting the balance wheel in all positions, making the tourbillon effective for wristwatches. The Double Tourbillon 30° Technique won the 2011 International Chronometry Competition with a record score of 915 out of 1000 points.