General Finishes Exterior 450 Outdoor Top Coat is a clear-drying finish suitable for vertical exterior surfaces, such as fences, patio furniture, garage doors, entrance doors, and interior windows. It is not recommended as a deck finish. The exterior 450 outdoor top coat is fortified with UV absorbers to stabilize the finish and built-in mildewcide to retard mold and mildew growth. It performs well as a clear coat or as an optional topcoat over General Finishes Milk Paint.