In 2007, Cartier unveiled the Ballon Blue collection. The watches have a sleek, rounded case that resembles a smooth pebble. A standout feature is the recessed crown, which leaves a subtle dent on the dial. Take the WJBB0007 model, for example. It boasts a yellow gold case surrounded by a bezel adorned with sparkling diamonds. The silver dial is a classic touch. Inside, the self-winding caliber 049 keeps the time ticking with its reliable movement. And to complete the luxurious look, the watch comes with a matching yellow gold bracelet.