RV PolyPRO 3 5th Wheel Cover XT 37-41 ft. This cover is especially designed for extra tall 5th wheels, with zippered panels that allow you to access the front, passenger side, and rear without having to completely removing it! The top is made of triple-ply Polypro 3 and the sides are thick single-ply Polypro to protect against rain, snow, dirt, nicks, and scratches for all-season protection. An integrated air vent system combined with the quick-drying sides reduce wind stress and vent inside moisture. The adjustable front and rear tension panels combined with elasticized hem corners provide you with a custom fit, while the integrated rope attachment system with toss bag will reduce the need to crawl under your RV.