The Coverking Deluxe Presidium Fifth Wheel RV-Cover is outstanding and provides amazing protection for your vehicle. Made from 600-denier polyester it is rougher and thicker than the average universal RV-cover. The 600 number refers to a type of polyester thread count in 1 intervals (the higher the thread count the tougher it is). All seams use an advanced double-stitched method to ensure that the gray 5th wheel cover remains water-resistant even at the closure. It is also quite breathable to ensure that moisture is kept out of the cover. Ventilated air-flats are also aligned around the top edge to reduce wind friction and to prevent moisture buildup. The cover also comes with built in zippered-door-flap for easier in and out access. To keep the breathable RV-cover in place included are adjustable buckles integrated on opposite ends.