Keeping the underside of your car protected is more important than you may think; even on your daily driver. Most "rotted out" vehicles you see started rusting in the underbelly of the car or truck. These are the areas that weren't protected properly from the factory or had a poor coating that broke down from year-round driving. On 4x4 and Off-Road vehicles the risk of road salt isn't as bad as the damage caused by driving over "stuff" (that's the fun of it right?). Your factory coatings aren't going to hold up to the rock chips, brush, etc dragging under your vehicle. The truth is, no coating can withstand some of the extreme conditions seen when rock crawling or off-roading. Think about it, if it damages the metal, NO coating is going to be able to withstand that sort of impact. But there are some coatings, or combinations of coatings that can hold up better than others. I put together a list of a few of my favorites below.