The Cartier Ballon Blue collection made its debut in 2007, boasting a sleek and rounded case resembling a pebble. One of its standout features is the recessed and safeguarded crown, leaving a distinctive "dent" on the dial. The reference W6900551 version showcases a shiny yellow gold case and a classic silver dial. Keeping it ticking is the automatic caliber 049, complemented by an elegant alligator strap.