Item Information Cartier continues to reign as the master of watches with its latest collection, Clé de Cartier. With soft curves, clean lines, and a rounded profile, the Clé exudes a minimalist elegance. The design is a testament to precision, balance, and proportion. Great mastery went into creating fluid lines and a harmonious design. The 35 mm and 40 mm Clé de Cartier models house the caliber 1847 MC, the new Cartier Manufacture Movement.