English: Greubel Forsey's Double Tourbillon Technique features their Double Tourbillon 30° regulator, four fast-rotating co-axial barrels and a visible spherical differential driving the power reserve indicator. At the 2011 International Timing Competition held by the Horological Museum in Le Locle, Switzerland, a Greubel Forsey Double Tourbillon Technique took first prize overall, as well as first prize in the Tourbillon category.