Artists Luciano Foglia and Bas Horsting started the Silent Shout Project as a collaborative project between artists around the world. Each of the five participating artists were asked to send a "message" to a recipient of their choosing in the form of a sound emitted through the mini sound installation boxes (speaker, plus sound module and batteries that last a couple weeks).
The speakers on the device face outward and the chips are programmed to play the sounds at intervals, so various people along the package's journey become the actual recipients. We're not sure how the postal service deals with weird noises coming from boxes, but the concept is definitely interesting. Listen to the sound that artist Dick Verdult included as the first installment of the project: