Vortex Marine Grade Canvas Top 20.5' to 21.5' Class B All Weather Motor Home Motorhome/Customized Van Cover (FAST SHIPPING - 1 TO 4 BUSINESS DAY DELIVERY) 600 denier marine grade canvas top with 3 layer polypropylene fabric sides repel rain and vent inside vapors out. Designed to protect your investment from Harsh UV rays and keep interior cool. Superior water resistant yet breathable to prevent any mildew inside of the fabric. Customer Support: 1-800-309-5190 (8:30 am - 4:30 pm) Monday - Friday Full-Height zippered panels allow complete access to your RV regardless of door location.