GF's Exterior 450 Stains are low-VOC, premium-quality, exterior pigmented water-based wood stains designed for outdoor projects with vertical surfaces, such as garage doors, entrance doors, and furniture. Can be applied to wood, MDF, and fiberglass, and are also made with more than 50% RENEWABLE RESOURCES. These stains are not recommended for large horizontal surfaces such as decks. Exterior 450 Stains contain U.V. absorbers to protect the finish and mildewcides to slow mold and mildew growth, but will not prevent the wood from changing color in sunlight. Brush or spray.