GREUBEL FORSEY. AN EXCEPTIONALLY FINE AND RARE 18K WHITE GOLD SEMI-SKELETONISED INCLINED DOUBLE TOURBILLON WRISTWATCH WITH POWER RESERVESIGNED GREUBEL FORSEY, DOUBLE TOURBILLON 30° MODEL, NO. 83, MOVEMENT NO. 0693, CASE NO. 00636, CIRCA 2008Movement: Cal. GF02, manual, 39 jewels, signedDial: Aperture with inner tourbillon inclined at a 30° angle rotating once every 60 seconds, outer tourbillon rotating once every 4 minutes, signedCase: Glazed display back secured by 6 screws, 43 mm. diam., signedWith: 18k white gold Greubel Forsey double deployant clasp. Certificat de grand service dated 22 August 2008 and undated Owner’s book, Greubel Forsey Extrait du Grand Livre and Certificat de Grand Service. This certificate is valid during six months following the date of acquisition of the watch at Christie’s, offering the new owner a free servicing (but not exceeding 10,000 CHF of the retail service price) of the present watch in Greubel Forsey’s workshops, subject to conditions published on the back of the Certificate.