Sunbrella fabric is water repellent, mildew and UV resistant. Plus, Sunbrella fabric is woven, which makes it breathable, so it doesn't trap heat and moisture like vinyl. Nor will it tear or shrink. This is not a generic mass produced cover. This is a custom boat cover, measured and designed specifically for the Highfield Ocean Master 460. Cover will fit over 2 and 4 stroke outboard motors in the up or mid motor position.