Sweetwater 37' - 40' Class A Motor Home Motorhome Cover (Ships Same or Next Day) Polypropylene fabric repels rain yet vents inside vapor out Easy On/Easy Off Cover designed to protect your investment from Mother Nature Superior water resistant yet breathable to prevent mildew inside of the fabric Customer Service: 1-800-309-5190 8:30 a.m. - 4:30 p.m. Monday - Friday