The Cartier Santos Triple 100 was first launched in 2008 in a limited edition of 20 pieces, cased in palladium. It featured three dials – in white, diamond pave and a hand-engraved tiger – made possible by a patented louvre system operated by the crown. Three-faced louvres made of solid white gold with a triangular profile are rotated to show each of the dials. The simplicity of the concept belies its complexity.

A cross-section of the Triple 100 dial 

A year later Cartier unveiled a second jewelled Santos Triple 100 with an eagle on one of the dial faces, also in a limited edition of 20 pieces. Like the tiger of the year before, the eagle is hand-engraved and requires about 50 hours of work.

The Triple 100 from 2009

That year Cartier also presented a Santos Triple 100 skeleton, informally known within Cartier as the “Double 100”, in a limited edition of 100 pieces. Unlike the Triple 100 that has three-faced louvres, the Double 100 uses slats with a rectangular profile, much like those of a window. Each face of the slats has one dial – white and black – hence the name Double 100. But the louvres can be also set such that the skeleton movement is visible, giving it three distinct looks.

The calibre used is the in-house, twin barrel 9611 MC with Roman numerals incorporated into the bridges and base plate to striking effect. First seen in the Santos 100 Skeleton, the 9611 MC was designed from the ground up as a skeleton movement, rather than being a skeletonised version of existing calibre. Thus it is remarkably transparent and totally different in feel from traditional skeletons, which were the intentions of Carole Forestier, head of technical development at Cartier and creation of the movement.

Shutter or louvre mechanisms on watches are not new. Such wristwatches were first available in the 1920s, notably from Vacheron Constantin, and were designed to protect the crystal from damage during sports, much like the Jaeger-LeCoultre Reverso. And in the mid nineties VC created the Les Historiques Jalousie which was inspired by the originals of the twenties. JLC currently offers the Reverso a Eclipse that features a roller shutter above an enamel dial. But the Cartier Santos Triple 100 is notable for several reasons:

1. The louvers are operated by the crown, an elegant solution unlike others which use buttons or slides.

2. Being under the crystal, this is also a more robust solution which is less prone to jamming and damage.

3. It features three different distinct dials.

Simple as the idea is, it took nearly three years to realise. The challenge was in creating a mechanism that would be easy to operate but remain firm when jolted. Carole Forestier and her team devised a solution of star-shaped wheels with tensioning springs to secure the louvres.

An illustration of the mechanism  

Each star-shaped wheel is held in place by a tensioning spring; the springs are actually part of a single strip of steel that runs the length of the dial. It is fabricated from a Durnico, a steel alloy with “high spring property” according to the manufacturer. Each spring measures only 0.6 mm wide – a human hair is about 0.1 mm wide.

Yet the levers provide just enough tension to keep the louvres in place while being flexible enough to allow rotation via the crown. The tensioning springs also give the Triple 100 the right feel – definite and reassuring, not mushy or stiff. Because of the delicacy of the springs, assembling and adjusting the shutter mechanism is not unlike doing the same for a complicated movement. Each spring and star wheel has to be adjusted individual to ensure each possesses the right amount of tension.

The crown set with a sapphire operates the louvres

The case is palladium and beautifully finished with polished bevels

The Cartier secret signature in the "X"  

The Triple 100 is an example of the sophisticated, yet unusual horological ideas that have been emerging from Cartier in recent years. Though it is not a complication in the traditional sense, it certainly is complicated enough.

- SJX

More of the two faces of the Double 100