Triple-ply PolyPRO 3 keeps out rain and snow. Thick, triple-ply top and single ply sides protect 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 Adjustable front and rear tension panels and elasticized hem corners provide a custom fit Integrated rope attachment system and a provided toss bag helps reduce crawling under the RV Classic Accessories Overdrive POLYPRO 3 DLX 5TH Wheel/Hauler Cover,FITS 37'-41'