Basic Principle of ShieldMAX operation:

RUST AND CORROSION: Forms on a moist iron surfaces, as a chemical reaction produces and electric current. The current causes dissolved iron and decomposed water to form ferrous hydroxide, which then combines with oxygen to make RUST.

Corrosion is a continuous destructive attack on metal that leads to wasting of the metal and the eventual failure of the structure or component made from the metal. The most common form of corrosion is iron oxide, better known as RUST. The rusting of iron is one of the most common examples of oxidation. Indeed the final fate of most iron and steel articles (your vehicle) is to be destroyed by RUST.

Electronic conduction - An electric current flows when charged particles move under the influence of an electric field. An electric field is a voltage gradient - that is, it can be considered as a slope down which he current flows - and is measured as volts per unit distance, typically volts per meter. There exists for example a voltage gradient (electric field) between the terminals of a battery. Moving the terminals closer together or increasing the voltage would increase the gradient, and hence the field strength. Just as a ball rolls faster down a steeper slope, this makes he charged particles accelerate faster.

Within an electric field, free negatively charged particles are accelerated toward the positive electrode (anode) while positively charged particles move toward the negative electrode (cathode).
Where both types of charges can move, the total current is he sum of the two. ELECTRONS are extremely small and mobile particles carrying negative charges and are the predominant particles involved in most conductive processes in materials. PROTONS, which are particles carrying positive charges, are larger and about 1800 times more massive than electrons. Furthermore, in most atoms protons group with neutrons (having no electric charge), making them even more massive and difficult to move compared with electrons.
Most materials, whether they are solids, liquids or gases, consist of atoms and molecules in a stable and neutral form, that is, a nucleus of protons and neutrons surrounded by the correct complement of electrons to exactly balance the number of protons. But, if atoms were so stable, it would seem impossible for conduction - which is the free movement of charges in an electric field - to occur.
Electrical conduction in metals, the electrons exist as a "cloud" and are easily moved by an electric field.
The particle or ball like description of charges is insufficient to explain all the characteristics of electric currents in certain materials and for satisfactory explanation it is necessary to consider more complex physics, such as QUANTUM MECHANICS.
Metals are excellent electrical conductors. Their atomic nuclei form regular (crystalline) structures surrounded by what is called and electron cloud or gas, WHICH PERMEATES THE WHOLE STRUCTURE. This term arises because the electrons that come from the outer orbits of the metal atoms (one or two from each atom) are extremely mobile.