Among the most sophisticated chains produced by ZMC, are those employed in the automotive pre-treatment process.The application of protective layers that precede the final painting of the cars, vans and trucks, takes place in pre-treatment plants, through which the chains follow the path of a sine wave. Two parallel chains slide on side guides which support steel carriers and in turn carry the car body.The process of applying corrosion inhibiting layers is achieved by conveying the car body through chemical baths. The nature of the conveyor path, having many rises and falls, is called the Pendulum system, and the chains take the same name.More recent systems allow the car body to also be rotated inside the chemical bath for more effective surface coating, this type of system is called Ro-Dip.There are significant technical challenges to be considered in providing chains that operate in these applications. The chains are highly stressed from a mechanical and corrosion resistance point of view. Innovative features include the choice of materials suitable for the operating environment, (in some cases Duplex stainless steel) the design and construction of sturdy bearing wheels, and an internal lubrication facility to operate with automatic lubrication systems.