Rust preventitive. They coat the bottom of the car, pump the bottoms of the doors, put stain protectant on the leather, and something on the paint. I wanted it for the underbody coating and door coating.... Even though i dont plan on driving it to much in the winter, salt is bad here in iowa. I got the auto because of the wife.... She didnt want to drive a manual with a car this powerfull. So it was either compermise or i buy a New Taurus.