Cartier Tank Must SolarBeat ref. WSTA0060, complete set

The Cartier Tank traces its origins to 1917, when Louis Cartier drew inspiration from the stark geometry of the Renault FT-17, with the brancards echoing the vehicle's treads and the case standing in for its cockpit. The Must, however, draws more directly from the Tank Louis Cartier design introduced in 1922 and briefly known as the Tank à Bords Arrondis, or “Tank with Rounded Edges,” before receiving its designer's name in 1924.

When Cartier launched the Tank Must in 1977, it represented a deliberate shift in the brand's commercial philosophy: a non-precious metal, quartz-driven watch produced at scale as luxury became increasingly accessible to a wider market. The strategy was immediately transformative, with Cartier's annual output growing from roughly 3,000 watches to hundreds of thousands in the years that followed. The design’s softly rounded, elegant profile quickly became one of the defining shapes of the late 1970s and 1980s, and is still instantly recognizable today.

Though the original Must de Cartier Tank line was discontinued in the mid-2000s, Cartier revived the Tank Must collection in 2021 with a new generation of models, including the solar-powered WSTA0060. This watch refines the classic Louis Cartier formula for contemporary wear, dropping the “Must de” signature on the dial and opting for stainless steel construction in place of earlier gold-plated cases. Cartier's familiar signatures remain intact, including a silvered dial with Roman numerals and a chemin de fer (“railway”) minute track, blued-steel sword-shaped hands, and blue synthetic cabochon-shaped spinel set into the beaded crown.

At the heart of this Tank Must lies Cartier’s innovative SolarBeat™ photovoltaic movement, marking the Maison’s first foray into solar-powered watchmaking. The challenge for the development team was to seamlessly integrate solar power while preserving the Tank's iconic dial. Their solution was a series of nearly invisible perforations within the Roman numerals, allowing light to reach photovoltaic cells concealed beneath the dial. The result is a watch that, unlike one with a traditional quartz movement, can run for at least 16 years before its rechargeable battery needs replacing.

The non-animal strap is made from approximately 40% plant-based material derived from apple waste, designed to lower the strap's carbon footprint and save water and energy compared with manufacturing a calfskin strap. The apples are grown and their waste collected within Europe, supplying a production chain that runs from the material site in Italy to the strap maker in Portugal and on to watch assembly in Switzerland.