Cant figure out what this component could be?

Picture: http://www.ifixit.com/blog/2011/05/

In the second picture on the linkpage there is shown the audio ic in right corner squared in orange color.

But just above this ic, there is a component. It looks like a square with round edges. And its black. When i look at the sides it seems to have 4 connections soldered to the logic board.

Any one can tell me anything about this component?

Maybe how its called? What it does?

Thank you for trying to help me in this!

Regards Vincent