fixed hub. The cabin is equipped with numerous storage compartments and the luggage compartment is regular in shape, with a capacity of 352 liters, increasing to 1,200 after lowering the rear seat backrest. The load threshold is quite high, hitting loads of heavy objects. There are laminated side windows and exterior mirrors, with a casing specially designed to prevent wind noise and improve the comfort inside. The saloon version is manufactured in Argentina, where it is sold alongside the five-door and the imported three-door version. The C4 Saloon is exported from there to Brazil and Hungary as the C4 Pallas and to Spain, Turkey, and Greece as the C4 Sedan. A longer four-door saloon version with a different rear end is also built and sold in China as the Citroën C-Triomphe. A panel van based on the coupé bodyshell is available in some markets, including Ireland. Technology A major selling point of the C4 was its extensive use of technology. For example, the car features the "lane departure warning system" (only in the top-of-the-range "exclusive" model), which alerts the driver if he or she crosses a road marking without using the turn signals; directional headlights; perfume dispenser integrated into the ventilation system; translucent dashboard; transparent glass roof; electronic stability program (ESP), and a fixed steering wheel hub, which lets the driver operate several functions of the car without removing their hands from the wheel. The fixed hub also allows for the first production use of a "shaped" driver airbag. Because the hub maintains a constant position, the airbag can be optimally shaped to spread the load across the greatest possible area of the driver's body in a collision, thus reducing the chances of serious injury. In addition, the car features an innovative centrally mounted translucent LCD speedometer display that remains clearly visible in all lighting conditions. The car's in-car entertainment, integrated into the car's information system via VAN bus, is not Digital audio broadcasting (DAB) ready. MP3 playback is supported by the entry level audio system and high-end audio, with double-layer sound-insulated windows and integrated navigation system available as extras. In September 2007, a USB box accessory (Ref: 9702.EZ) was released to enable full iPod connectivity with the standard RD4 radio. The C4 does not feature Citroën's Hydractive suspension, which is reserved for higher class models, such as the C5 and C6. The Picasso version can feature a pneumatic rear