The Coverking Deluxe Travel Trailer RV Cover Presidium 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 covers remain water-resistant even at the closure. This Coverking cover for RV is also quite breathable to ensure that moisture is kept out of it. Ventilated air-flats are also aligned around the top edge to reduce wind friction and to prevent moisture buildup. This RV trailer protective cover also comes with built-in zippered-door-flap for easier in and out access. To keep the RV-cover in place, included are adjustable buckles integrated on opposite ends.