Cartier, complete set, Ballon Bleu series, model: WSBB0040, diameter 40mm, automatic mechanical, stainless steel: 40mm, thickness 12.45mm, is a very popular unisex / men's size in the Ballon Bleu series Movement: Equipped with Cartier's self-produced 1847 MC automatic mechanical movement, it features stable timekeeping and anti-magnetic design Appearance design The stainless steel case and strap, paired with the signature grooved crown, are set with synthetic spinel Silver-plated guilloon-patterned dial, with Roman numeral hour markers and blue steel hands There is a date window at the 3 o 'clock position, and the case back is a solid case back design