Jacob & Co. has just released three timepieces from its Twin Turbo Furious collection that features both a fully transparent sapphire crystal case and a decimal minute repeater, a first in the world of Haute Horlogerie.

“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 utterly see-through 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. The collection also features a 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.

TT Furious Sapphire Green Rubber

When it comes to contemporary high-tech watchmaking, creating 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 that took nearly nine months to develop. 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.

There are plenty of obstacles with a challenge like this; contrary to the standard five-sided 57mm by 52mm case made of 88 components, this case was reduced to just a handful of parts. This included 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 the sapphire crystal is the 18k white gold crank at 3 o’clock that winds and sets the many complications. Hand polishing is the most crucial part of the process because it gives the sapphire crystal transparency. Every technique that is used in hand polishing crystal was incorporated throughout the different details of the case. The back cover was equally challenging to complete because of the varying angles and planes.

TT Furious Sapphire Red Rubber

Several compromises in the watch’s design 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 sound made this a unique achievement.

The collection includes the “Bugatti Blue” timepiece, which celebrates Jacob & Co’s partnership with of high-performance sports car manufacturer, Bugatti. The watch dedicated to Bugatti has a “Bugatti Blue” Neoralithe chapter ring. The color honors Bugatti’s history and French heritage. This model also features the company’s logo on the front of the sapphire crystal case.

TT Furious Sapphire Clear RubberWhat 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 watches continue the tradition of the Twin Turbo Furious of being a sports watch inspired by the speed and beauty of high-performance automobiles with a group of complications that are novel in the world of Haute Horlogerie. Inspired by the rate and beauty of hypercars, each of these watches is being produced in a limited edition of six pieces. The sapphire crystal is one more example of how Jacob & Co. makes the impossible a reality.