What does "Ballon Bleu de Cartier" translate to (French to English), in relation to this print advertisement?

I’m going to be giving a final, which asks my students to analyze an advertisement based on Maslow’s hierarchy of needs. This is the closest I could find for the ad on the ‘Net:

http://www.thecartierwatches.com/blog/wp-content/uploads/2012/11/luxury-cartier.jpg

The ad I’d like to choose is a challenging one, in print, that advertises this watch, by Cartier: http://www.ballonbleu.cartier.com/#/esprit

It seems that the name of the watch is Ballon Bleu de Cartier. What does that translate to, other than the name of the watch?