Electronic rust control module. Science or Scam?

The one thing that you can do and it will not cost you a penny. If you use the car as a daily driver, do not park your car indoors. Leave it outdoors so it does not defrost. You will get ice and salt on the car and it will freeze. While it is frozen the salts do not contact the metal and does not do damage. If you park indoors, the ice will melt and the liquified salt with run all over the metal and then you will do the same every day after that. If you leave it outdoors, the salts will only affect your car one or two times in the spring