Mystery Door Part

[p_rubottom]

For awhile now my wifes suburban has had stereo problems. It has been cutting out and crackling real loud, I have pulled the radio several times looking for a loose wire here and there but finally i pulled all the door panels and started tracing wires from the speakers in. I got to the drivers door and found this part on the magnet which was laying across the speaker wires causing my problems, now I'm trying to found out where its from? Can anyone tell me what it is? There are no electrical connects or anything to help look for where it belongs.