Duck Covers RVCB240 Globetrotter Gray 18' - 20' Class B RV Cover 100 percent breathable, water resistant top panel reduces mildew Air vent system and quick drying Globetrotter fabric combine to reduce wind lofting Adjustable front and rear tension panels and elasticized corners reduce slack and provide a custom fit Zippered panels for access during storage; long zipper pulls reduce the need for a ladder Integrated nylon strap attachment system with buckles and weighted toss bag included