Stellex Personal Watercraft Cover Blue Medium. This is an all-season travel cover with an integrated trailering system made of tough polyester Stellex fabric designed for durability and weather protection. Its integrated trailering system with built-in quick adjusting side-release straps, zippered access doors on both sides, and elastic cord in the bottom hem, the fit is quick and secure. Rear air vents reduce inside moisture and wind lofting, and the tension panels tightly secure the cover for highway travel. Built-in strap keepers secure excess straps after tightening.