The Cartier Ballon Blue line was introduced in 2007. It features a smooth, pebble-like case. One of its signature elements is the recessed & protected crown and the 'dent' it causes in the dial. The Extra Flat 46mm was introduced in 2011, while the Extra Flat 40mm was introduced at SIHH 2015.
Reference HPI00586 has a white gold case of 46mm, which houses its hand-wound caliber 9452MC with flying tourbillon. The case is set with 114 baguette-cut diamonds totaling 4.80 carats; the dial has 120 baguette-cut diamonds totaling 2.52 carats.