Sharing / Earphone

Sharing is a virtue that could be easily achieved by a small action, like sharing your favorite songs or your new mp3 player.
You can likewise achieve this goal by using these earphones, which could conserve energy and reduce the production of mp3 players.
When I take a bus with friends , I always hesitate about sharing my earphones or not. If I give them one of my earphone , I would have to tolerate the noise from the outside world. But if I don't, I would see myeslf selfish.
So I came up with an idea that could not only solve the
problem above, but also conserve energy and reduce production of mp3 players by a simply act of share.