Reply by Brian Strothcamp

http://www.aqua-man.com/itemMatrix_all.asp?GroupCode=M5619

use this stuff its SPF40… seal your wood with something oxygen cant penetrate (no wax finishes)
i have used it with great success… its excels even in direct light

i have been using this on vinyl hot tub covers for years (its highly recommended for this purpose in the spa world) usually one treatment a year is all thats needed and that says a lot, never had a cover fade and they have always been in direct sunlight.