The Duchess of Cambridge (Kate Middleton) owns the Cartier Ballon Bleu watch. She wears the 33mm size.
The watch mechanism is set in a stainless steel case and attached to a stainless steel bracelet. The watch has a silvered opaline dial with blue sword-shaped hands and Roman numeral hour markers and a blue synthetic spinel cabochon.
Where to buy the Cartier watch:
Jomashop.com currently sells the watch for $4,115 (in their memorial day sale). RRP is $5,200.