Breathable covers support efforts to minimize corrosion by removing moisture from beneath the protective cover. Breathable covers should prevent water from getting in while allowing water vapor to escape. These two characteristics, waterproofing and moisture permeability, are mutually contradictory. So how does that work?
First, let's clarify one thing: Breathability should not be confused with wicking. We've all heard of wick-away apparel for athletes. The fabric used in these clothes works by moving water (sweat) away from the surface being protected (the body). Breathable covers do not work this way.