Cartier, Blue Bubble de Cartier, Cartier Blue Bubble watch, model: WGBB0009, automatic movement, 750‰ rose gold case, diameter: 36.6 mm. Signature feature: a domed spherical crown set with a blue spinel at the 3 o'clock position, a hallmark design of the Ballon Bleu collection. The dial features a double-layered design with radial and sunburst patterns, complemented by Roman numerals and blued steel leaf-shaped hands.