This is a rather bad picture of my hearing aid. Hopefully you can get an idea of how it works though. At the top of the picture at one end of the headband is the bone conductor that transmits the sound vibrations through my skull bone. At the other end of the headband, the bottom of the picture, is the part of the hearing aid the takes in the sound, changes it into electrical energy, and also holds the battery. The battery chamber is open and part of the battery can be seen in the picture. A wire runs over the headband and connects the two parts of the hearing aid.