These half round Filter Flow gutter guards are a polyether foam filter insert that prevents leaves, pine needles and large debris from clogging a gutter system. Leaves and debris slide off the surface or just dry up and blow away.
Filter Flow has a Proprietary Coating Process that has a UV stabilizer that prevents degradation from the sun. It includes a germicide that inhibits the growth of mold, mildew, fungus, algae and moss. It also prevents mosquitoes, wasps bees and other insects from breeding in the gutter.