Jacob & Co. unveils first Minute Repeater in Sapphire Crystal Case

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September 2021

Jacob & Co. unveils first Minute Repeater in Sapphire Crystal Case

Jacob & Co. releases three timepieces from its Twin Turbo Furious collection that feature both a fully transparent sapphire crystal case and a decimal minute repeater, a first in the world of haute horlogerie.


acob & Co. latest release includes the “Bugatti Blue” timepiece, which celebrates the iconic manufacturer of high-performance sports cars. Each of the new watches, inspired by the speed and beauty of hypercars, is being produced in a limited edition of six pieces.

“Even after 35 years, we continue to create timepieces that are groundbreaking and innovative,” says Jacob Arabo, Founder of Jacob & Co. “Creating a watch with a transparent sapphire case and a minute repeater is a revolutionary concept that was extremely difficult to achieve. We are proud to be the first watch brand to achieve this difficult feat.”

The sapphire crystal case provides a full view of the complex machinery of the Twin Turbo Furious, powered by the manual winding JCFM05 movement with a 50-hour power reserve. This includes the groundbreaking group of exclusive complications, such as the decimal minute-repeater, twin high-speed tourbillons, mono-pusher chronograph, and a pit-board style reference indicator.

When it comes to contemporary high-tech watchmaking, the creation of a sapphire crystal case is one of the pinnacles of achievement. The unique shape of the Twin Turbo Furious sapphire crystal case made this an even more challenging project. Developing the design took nearly nine months. Producing the case by first growing the sapphire crystal from aluminum oxide, then shaping the case through a combination of state-of-the-art numeric machinery and detailed hand polishing took another six months for each case.

Jacob & Co. unveils first Minute Repeater in Sapphire Crystal Case

The obstacles were plenty. Normally the five-sided 57mm by 52mm case is made of 88 components. This was reduced to just a handful of parts, including the main case, the front and back sapphire crystal covers and the slide at 8 o’clock that activates the decimal minute repeater. The only part of the watch that isn’t made of sapphire crystal is the 18k white gold crank at 3 o’clock that winds and sets the many complications.

The case has several geometric planes and angles that made both the machining of the case and particularly the hand polishing quite difficult. The watch’s unique twin-bezel design provided additional challenges. Hand polishing is the most important part of the process because it gives the sapphire crystal its transparency. It was also the most difficult to achieve. Every technique that is used in hand polishing crystal was incorporated throughout the different parts of the case. What was just as difficult as the main case to complete was the back cover, again because of the varying angles and planes.

Several compromises in the design of the watch were made to allow for the gongs and hammers of the decimal minute repeater. This is the first watch ever to incorporate a minute repeater inside a sapphire crystal case. The complexity of placing this complication inside the watch and ensuring the high-quality of the sound made this a unique achievement.

Jacob & Co. unveils first Minute Repeater in Sapphire Crystal Case

These new limited-edition models have all the exclusive complications and features that made Twin Turbo Furious a groundbreaking timepiece when it was first released in 2018, including: an hours and minutes dial with a small second indicator at 9 o’clock; a mono-pusher chronograph with a minute counter at 3 o’clock and a centered small second hand; a reference time indicator with minutes displayed at 6 o’clock, seconds at 12 o’clock, reference time differential displayed by chronograph second, and a hand on dial-trained “pit board”; the decimal minute repeater that chimes on the hours, every 10 minutes and minutes; a twin triple-axis high-speed tourbillon; and a power reserve indicator at 6 o’clock.

What separates the three watches is the Neoralithe chapter ring that surrounds the dial of each. One is in bright red and the other is in green. Neoralithe is a man-made material produced from resin and developed in Switzerland. It is known to be resistant to UV light and thermal or physical shocks. It also provides a great contrast in color to the transparent sapphire crystal case.

The watch dedicated to Bugatti has a “Bugatti Blue” Neoralithe chapter ring. The color honors Bugatti’s history and French heritage. The Bugatti model also features the company’s logo on the front of the sapphire crystal case.

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