The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From Fiat Group Automobiles S.P.A:
Fiat 500 TwinAir: The application for iPhone and iPad that reveals the most environmentally-friendly patrol engine in the world.The application Fiat 500 TwinAir introduces you the most environmentally-friendly bi-cylindrical patrol engine in the world, leading you to the discovery of its technological advantages and letting you have fun with its playful tracks such as PlayTwin, a game of a real skill behind the wheels of the 500.Thanks to the application it is possible to follow an interactive timeline of Fiat technological innovations, based on both eco-sustainability and driving pleasure.