Some fabric materials may vary for your specific needs on the road, such as how much heat or cold your awning is going to endure on your journey. The most common and popular materials are Vinyl and Acrylic fabrics. Acrylic is where you get that breathable topper that will dry faster and is easier to maintain. Vinyl is where you're going to get that waterproof, sturdy topper that is just a little more expensive. Although these toppers look top-notch, it is very easy for them to build up mildew if not taken proper care of.