inside covering
2.The most materials of German Audi car are made of Galvanized steel (some part are made of aluminum alloy), America Buick car uses Galvanized steel that contains more than 80% two-sided Galvanized steel, Shanghai Passat uses electric galvanizing technology on out covering part, hot galvanizing technology on inside covering part, which can protect the car body out of rustiness more than 11 years.

