Originally Posted by
JDNSW
Also used on virtually all metal ships and boats that are permanently on the water, and used extensively in industrial situations. They all have one thing in common - the metal being protected is totally immersed in water. I know from experience that while electronic rust prevention stops the outside of my boat from corrosion below the water line, it does nothing for it above the water line, nor does it stop it from rusting from the inside. So go for it if your car spends its life below water.
John