GREUBEL FORSEY. A VERY FINE AND EXTREMELY RARE 18K WHITE GOLD WRISTWATCH WITH DIFFERENTIAL DOUBLE TOURBILLON AND POWER RESERVESIGNED GREUBEL FORSEY, ART PIECE 2 EDITION 2 MODEL, CASE NO. 03 509, CIRCA 2017Movement: GF 02W, manual, 35 jewels, signed Dial: Differential double tourbillon regulator with inner tourbillon inclined at a 30 angle rotating once every 60 seconds with the outer tourbillon rotating once every 4 minutes, signedCase: Sapphire shutter operated by the pusher at 4 hiding or revealing the time indication, glazed display back secured by 7 screws, 44 mm. diam., signed With: 18k white gold Greubel Forsey double deployant clasp, Certificate of authenticity, 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.