Cartier Ballon Bleu. This specific model appears to be in stainless steel with a silver guilloché dial, Roman numeral hour markers, and a diamond-set bezel.
Brand: Cartier
Collection: Ballon Bleu de Cartier
Case Material: Stainless Steel
Dial: Silvered guilloché with Roman numerals
Bezel: Set with brilliant-cut diamonds
Crown: Fluted crown set with a synthetic cabochon-shaped spinel
Comes with original box papers and Cartier paper bag