The round dial of the new Clé collection, with its classic Roman numerals and guilloché centre, houses a cutting-edge automatic movement developed and assembled by Cartier's watch manufactory in Switzerland, Calibre 1847. (Eric Maillet © Cartier)

The round dial of the new Clé collection, with its classic Roman numerals and guilloché centre, houses a cutting-edge automatic movement developed and assembled by Cartier's watch manufactory in Switzerland, Calibre 1847. (Eric Maillet © Cartier)