VELCRO Brand Industrial Strength Extreme fasteners feature an all-weather, UV-resistant adhesive for rough surfaces including concrete and certain types of brick. Superior holding power meets the requirements of demanding indoor and outdoor applications without drilling, nails, screws or epoxy. features A high-tech molded hook, and heavy duty, water resistant adhesive for superior holding power on smooth surfaces, including plastic, indoors and outdoors. Continued exposure to direct sunlight can damage fastener. Not recommended for underwater use. Adhesive reaches maximum strength after 24 hours. Not recommended for dashboards or flexible vinyl. Total weight not to exceed 20 pounds.