Semi-custom fit with strong yet supple fabric that will outlast any cover on the Market. Multiple zippered panels allow easy access to front, sides and back. 5 Year Warranty. If you are looking for something a little better, you just found the cover. The material that we use is a heavy-duty 6 oz. woven true loom Polyester with a state-of-the-art marine-grade finish. This fabric is water repellant and UV and mildew resistant. It comes with a 5-year warranty! Soft and Durable this cover is constructed of 300 Denier Filament Polyester Yarns. Stronger than Sunbrella or Tyvek, this is the best aftermarket cover available today. How to measure for Length: Overall length includes bumper and spare tire but not hitch. How to measure height: Bottom of trailer to the Top.