Iv got one in the back of the zaf. The people in the back of the car connect thier earphones and have thier own individual volume controls. If the driver has the CD player on, then the people in the back either listen to the same track as the driver or the radio. If the driver has the radio on then they can listen to the CD and select a track of the choice!
If no earphones are connected and the power button is pressed, then the back speakers can be turned off and on!
How cool is that!