Abstract: An air bag formed of thin flexible sheet material is mounted in a housing within a motor vehicle in a deflated condition and is rapidly inflatable for protecting an occupant in the passenger compartment of the vehicle. The air bag has an elongated, generally cylindrical shape when deployed to inflate for expanding directly and more rapidly from the housing into protective cushioning contact with the occupant thus reducing the chances that the occupant will be subjected to excessive movement or velocity relative to the interior of the vehicle and further reducing the possibility that the occupant will be subjected to unwanted contact with closely adjacent surfaces in a relatively small passenger compartment of the vehicle. The novel air bag is formed from three pieces including a pair of generally circular inner and outer end walls joined together with a cylindrically-shaped side wall.