In 2007, Cartier unveiled their Ballon Blue collection. It's known for its sleek, round case that resembles a pebble. A unique design detail is the protected crown, which creates a small dent in the dial. The W2BB0022 model has a stainless steel case, a yellow gold crown, and a silver dial. It runs on a self-winding caliber 049 and comes with a stainless steel and yellow gold bracelet.