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The World’s Thinnest Mechanical Watch, the New 1.70mm Bulgari Octo Finissimo Ultra COSC (incl. video)

Bulgari reclaims its title with the world’s thinnest mechanical watch just 1.70mm thick.

| By Xavier Markl | 5 min read |

The competition for ultra-thin watches is more intense than ever. Watches with a thinness that would have been unimaginable a few years ago have recently been unveiled, with manufacturers squeezing complications into minimal space and tirelessly chasing microns. Bulgari’s Octo Finissimo saga has garnered widespread recognition in this realm. The brand’s remarkable series of records included the world’s thinnest mechanical watch in 2022, the Octo Finissimo Ultra, at a mere 1.8mm thick. However, Bulgari‘s reign was short-lived, when Richard Mille introduced the RM UP-01 a few months later, with its 1.75mm thickness. But it’s time for Bulgari to reclaim its trophy and bragging rights. Meet the world’s thinnest mechanical watch with the new 1.70mm Bulgari Octo Finissimo Ultra COSC.

The Octo Finissimo needs little introduction and has become a true icon of horology. It is a statement of style and Italian elegance. Beyond its aesthetic appeal, it is also a technical achievement as slimming down watches to such extremes is a daunting task that demands the utmost precision and skill. With the Octo Finissimo Ultra, Bulgari held the record for the world’s thinnest mechanical watch until the arrival of Richard Mille’s astonishing RM UP-01. But it’s time for Bulgari to snatch back the record with the 1.70mm Octo Finissimo Ultra COSC.

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From a technical perspective, the Ultra COSC relies on the same principle as the first Octo Finissimo Ultra. Developed with movement specialist Concepto, such a technical achievement pushed the limits of ultra-thin manufacturing, trimming down the components and working with the most extreme tolerances. It also required out-of-the-box thinking, with a complete reengineering of the entire watch, reimagining each component, its architecture and its functions. The development involved the filing of no fewer than eight patents. And the assembly of a single movement/watch requires about a week, which gives us an idea of the precision required when working with such tight tolerances.

Just like the Piaget Altiplano Ultimate Concept, the caseback of the Finissimo Ultra serves as the movement’s base plate. The idea is to avoid having different layers in the watch architecture, taking advantage of the entire surface of the watch and rearranging and building all functions on the same horizontal plane. The regulator-like display with separate time indications avoids superimposed hands. Instead of a standard crown, two horizontal knobs are placed on each side of the case – one for winding and the other for time setting. Three rollers drive the rotation of the oversized barrel. The balance is fitted with a flat spring, has no index and features adjustment weights. It is held in between flexible bridges that will deform in the event of a shock – for more details you can check out our video on the original Finissimo Ultra. 

To become thin enough to reclaim the record, the shape of the bezel, crystal, dials, and barrel of the Bulgari Octo Finissimo Ultra COSC have been reworked. So, there is no revolution in the watch structure; overall, it feels very familiar. The same materials are used: tungsten carbide for the mainplate and titanium for the lugs, bezel, middle case and bracelet. It has the same monochrome grey finish although the hours and minutes dials are more contrasted. One change, though, is that the ratchet features a geometric pattern instead of the QR code engraving. The QR code has been replaced by a miniaturized Datamatrix on the back of the watch; it provides access to all the data relating to the watch and invites you on a personal journey into the Bulgari universe.

As its name suggests, the Bulgari Octo Finissimo Ultra COSC is also chronometer-certified, showing that it is not just a concept watch or prototype—which is no small feat. Each watch will have to go through the COSC tests, which last 15 days with different positions and temperatures. Naturally, this also makes it the thinnest chronometer watch ever—and by far. 

Last, for this extraordinary timepiece, Bulgari has developed a very special box with a digital interface that allows you to wind and set the time of your watch. You just need to place the watch inside the case, enter the time, and, with the push of a button, initiate the adjustment cycle. Within moments, the watch is wound and set to the desired time.

The Bulgari Octo Finissimo Ultra COSC is a limited edition of 20 watches. It is priced at EUR 600,000. Last but not least, along with this 1.70mm Ultra COSC, Bulgari is also releasing another version of the 1.80mm Octo Finissimo Ultra in tungsten carbide and platinum, with blue hour and minute dials.

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3 responses

  1. Also looks much better than RM’s effort, which in all honesty looks like a watch in a mall special sale.

  2. Incredible. That’s haute horlogerie right there. Whenever Bulgari innovates and can’t help to think what happened with Piaget and what could’ve been. I guess that it wasn’t worth their while.

  3. congrats guys for the informative interview, and the watch itself is surprisingly ‘normal’!
    too bad no details on the unusual clasp mechanism!

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