Doe anyone know what the rubbery coating material is that coats the underside frame rails, and where to get some?

I had an incident involving a high curb (don't ask -- stupidity on my part involving not having the parking brake properly engaged) that scrtached up the undersides of the frame rails and peeled off some of this rubbery stuff. I assume it is there to protect the underside of the car from moisture and prevent rusting, so I'd like to get some to fill in the scratched areas.

 

I'd get a gallon of quietcoat.

http://www.quietcoat.com/