Exterior 450 Topcoat 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. Exterior 450 is fortified with UV absorbers to stabilize the finish and built-in properties to protect it outdoors. It performs well as a clear coat or as an optional topcoat over General Finishes Milk Paint.