PolyPRO™3 RV Deluxe Folding Camper Cover gray 18-20 ft. The thick, triple-ply Polypro 3 top and single-ply sides protect your RV against rain, snow, dirt, nicks, and scratches for all-season protection. An integrated air vent system combined with quick drying Polypro 1 sides reduce wind stress and vent inside moisture. With adjustable front and rear tension panels and elasticized hem corners, you get a custom, secure fit. Access RV doors and the engine area without removing the entire cover with zippered panels, so you know you can cover your RV and still maintain or use it while it is stored. Its integrated rope attachment system and a provided toss bag helps to reduce the need for crawling under the RV, and stuff sacks and ladder caps are included.