Side Air Bag Module
WARNING: This page is about a different car, the 2002 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The seat back cover is specially designed to allow air bag deployment. In certain lateral collisions, the side air bag module will inflate, even if the seat is unoccupied. The side air bag is designed to inflate between the door panel and occupant, adding enhanced protection.