Get complete protection for the underside of your new JK! Save money by ordering the complete kit- including 4 separate skid plates- gas tank skid, oil pan skid, transmission skid, and transfer case skid. The oil pan skid includes an oil drain panel that allows the oil to be changed without removing the skid. The oil pan skid bolts to our transmission skid that bolts to the Jeeps cross member. It allows the use of a long arm suspension kit without cutting. The transfer case skid replaces the factory skid and offers greater protection. And the gas tank skid covers the entire gas tank front to back. UHMW stands for Ultra-High Molecular Weigh Polyethylene and these 3/16" thick panels are specially designed for sliding over rocks. They can be used with the steel skids, but are not really necessary with the steel. We do recommend them if you are getting the aluminum. Our aluminum skids are made from 1/4" material and will protect your system, but they will get scratched if you wheel them hard so the UHMW protects the aluminum and helps them to slide over the rocks instead of getting scratched up.