Are All Undercoats Created Equal?

There are several good products. I have used Amsoil's Heavy Duty Metal Protector as an "undercoating". Apply annually. No build up, does not attract dirt / dust, etc. Aerosol can with straw for getting into all those tight little places. I even use it with good results on my heavy commercial trucks that live in the rust belt and operate in that slop all winter long.

The only "undercoating" I would consider is a product called "Mouse Free".

http://www.mouse-free.com