Usually they will spray bomb the interior with a Scotchguard type product. You can do this yourself for around $10-15.00. On the outside they will wash it and spray on a polymer coating similar to Rejex, Simoniz Ice, Nu Finish and others. They then buff this off. Normally they want to get it back each year to reapply this "special" coating. Sometime they charge for the reapplication, sometimes not. If you read their "warranty" it will usually consist of a partial refund if the product fails to do what they say it will do....Saw lots of these sold when I was in the car business for years. HUGH money maker for the dealer. One store I was at usually included this for no charge with a new car purchase, I guess it wasn't so bad then....If I was buying a new trailer and the dealer I was working with pushed this real hard, I would walk away and buy from someone else....Don