Hauraki Neoprene Fender Covers are the best you can get for protecting your gelcoat or paint job. The covers are reversible up and down, as well as inside out, meaning you can get up to 4 x the life out of them. They are manufactured in New Zealand from neoprene comprising of a soft-closed-cell foam rubber with a stretchable nylon fabric either side meaning they do not absorb water and are resilient to algae growth. The covers are a nice snug fit and do not need to be removed to inflate or deflate the fender.
Regular application of 303 Aerospace Protectant will further increase the life expectancy of the neoprene covers.