A German firm has proposed to transmit ads via train windows. The transmission makes the sound appear as if it "comes from inside the user's head" when passengers lean against them.
The idea would use bone conduction technology, a technique that transmits sound to the inner ear by passing vibrations through the skull, the BBC reported.
The concept has been developed by ad agency BBDO Germany on behalf of broadcaster Sky Deutschland.
The Talking Window campaign idea was shown off at the International Festival of Creativity in Cannes last month.
BBDO said it had received "highly encouraging first reactions" from commuters who tested the kit
The video shows passengers on a German train being surprised to hear ads urging them to download the Sky Go app on to their smartphones to watch streamed video.
The audio is created by a special Sky-branded transmitter made by Audiva attached to the windows.
Google also plans to use the tech in its forthcoming Glass headset.