The ADCO 34840 Tyvek Designer Series Plus Wind cover is made to fit 18'1" to 20' travel trailers. It is white and gray, with a triple-layered Tyvek top panel and triple layered polypropylene sides. Useful for every climate, this cover is especially resistant to wind and UV rays. The slip seam strap system fits the cover to the trailer, reducing the impact made by the wind. Built-in vents on the sides allow air to pass through, so moisture won't get trapped inside.