P OW E R PLAY

There’s no such thing as the perfect watch, but Louis Cartier got pretty close when he designed the Tank in 1917. Its form – a dial suspended between a pair of parallel lines – is about as simply elegant as it gets, and the model has remained relatively unchanged for more than a century. The new Solarbeat Tank Must, however, marks what might be the most significant update to the Tank in years. As the first-ever solar powered watch in Cartier’s history, this new Tank is powered by a photovoltaic cell hidden beneath its Roman numeral dial and can run for 16 years without requiring service. It also features a strap made from plant-based leather, another first for the Parisian jeweller. This kind of ability to evolve while retaining its essential form confirms that the Tank is as close to timeless as you can get.

Solarbeat Tank Must, $3,250 at Cartier (ca.cartier.com).