I am on my third Tyvek cover for a FF X-189 since 2006. During those 8 years I have owned two FF of the same length. Our Southern California sun and heavy winds are very hard on these covers, but I have not found anything yet which provides the same protection for the price. My current cover is two years old and "might" make one more year before it literally turns to powder on the triple layer roof area. I am aware that a heavy duck material like they use for quality boat covers would last about twice as long, but they are three times the cost and are too heavy for me to lift up a ladder and on to the roof of my relatively short FF. I noticed the Camping World internet price is currently $213 for this model which fits our FF size: ADCO Travel Trailer Designer Tyvek RV Cover - 18'1" to 20'. In my experience, that is a pretty good price.
After I bought my first ADCO cover from Camping World back in 2006, I began looking for a better price and found the exact same cover for much less directly from the Chinese importer in our area ($140). However, he told me he is no longer carrying the smallest (18'-20') cover. Good luck and stay safe putting your cover on and off!
Fun Finder 2006 X189FD sold
Fun Finder 2012 X189FBS sold
2016 Lance model 1995
2016 Ram 1500 EcoDiesel 4x4