It's a small audio streamer that allows you to use some common audio streaming protocols (Airplay for iOS devices, Spotify Connect for Spotify users etc) with a

It's a small audio streamer that allows you to use some common audio streaming protocols (Airplay for iOS devices, Spotify Connect for Spotify users etc) with audio line out for speakers & headphones. It looks like an open source version of something like a Wiim Mini which should give you something to search against to see what they do.