Galvanized steel mailbox - protection from rusting

Galvanized steel is created by dipping standard steel into molten zinc by a process called hot dipping. With galvanization, a piece of industrial steel is expected to last more than 50 years in average.

The zinc protects the base metal by acting as a barrier to corrosive elements, and the sacrificial nature of the coating results in a long-lasting and high-quality steel product. 

Rust resistance from the zinc coating. The iron elements in steel are incredibly prone to rusting, but the addition of zinc acts as a protective buffer between the steel and any moisture or oxygen.