Each shirt has unique art printed on the backside of the T-shirt. The smart phone app picks up that unique art through the camera, and augments the wings on your back. The smart phone app should be available for iOS and Android.
The demo video by COSPA can be seen here:
The shirts are already up for pre-order for 3,360 yen @ nijigencospa:
This is not the first use of augmented reality apps on smart phones. Fans of Minecraft might know, but Minecraft Reality by 13th Lab, is another great smart phone app that takes advantage of this new augmented reality technology. The Minecraft Reality app is powered by the PointCloud SDK which allows the mapping and tracking of 3D spaces using a technique called SLAM (Simultaneous Localization and Mapping). It makes me wonder if the COSPA app is also using the PointCloud SDK.