Sharkskin is a specially formulated polyester that weighs only 6.5 oz. per square yard. Still incredibly strong and durable, this cover provides outstanding protection for boats by repelling water, mildew, UV rays, and other foreign elements. Fade-resistant, breathable finish resists staining and prolongs cover life. 5-year limited warranty. Orders for Covermate Exact-Fit Covers cannot be canceled and are non-returnable and non-refundable. For a free Sharkskin Sample Card, order item number 314600. Covermate Sharkskin Plus Exact-Fit Cover for BLUEWATER 18 RIVIERA 18 RIVIERA BOWRIDER I/O. Royal Trailerable: Yes Material: 6.5 oz. 100% polyester