Watch of the Week: Greubel Forsey Double Tourbillon 30-Degrees Technique Sapphire

Courtesy Greubel Forsey

Get a crystal clear view into one of the most celebrated and innovative movements on the market, thanks to a fully transparent sapphire case.

It’s a mouthful to say, but the Greubel Forsey transparent Double Tourbillon 30-Degrees Technique Sapphire timepiece, unveiled to the world this summer, is also an eyeful to behold. Crafted using a totally crystal clear sapphire case—milled from a solid block of sapphire—the watch's handsome see-through exterior construction allows the wearer (and onlookers, too) a totally unobstructed view of its elaborate, complicated movement and its 396 parts.

Though the watch's hand-wound, patented movement, featuring a double tourbillon, is not new, it is one of the most beloved and lauded Greubel Forsey calibers ever made. By developing one tourbillon cage inside the other, angled at 30 degrees and each rotating at different speeds (the outer one completes a single rotation once every four minutes; the inner one rotates once every minute), Greubel Forsey achieved incredible chronometric precision. In fact, the accomplishment won the watch an unheard-of score at 915 out of 1,000 points at the International Chronometry Competition in 2011.

Here, the movement parts are meticulously finished with engravings, beveled edges, and black treatments, all the more interesting to witness through the clear 38.4mm case, which measures 12.15mm in thickness. The piece also touts four co-axial series-coupled, fast-rotating barrels that provide 120 hours of power reserve for a technical masterpiece.

Entirely exclusive to the U.S. market, only eight designs—each retailing for roughly $1.1 million—will ever be made. greubelforsey.com.