Difference between Underseal and Undercoat

What is the difference between Underseal and Undercoat?

Underseal as a noun is a thick, resilient coating applied to the underbody or chassis of an automobile to protect against damage from small stones, etc, which would rapidly chip ordinary paint and allowing rusting to begin. while Undercoat as a noun is a layer of short hairs underneath the longer ones of an animal's fur

We hope you now know whether to use Underseal or Undercoat in your sentence.