Flexlock Ultra Performance Concrete Adhesive is one of the strongest polyurethane adhesives on the market. It strongly adheres to concrete pavers, stones, retaining walls, masonry units and bricks. It is specially formulated for overlays, pool copings, steps and wall caps. Flexlock Ultra Low Voc Polyurethane Adhesive is designed to provide a permanent bond in 24 hours to the above materials if properly installed. It replaces solvent-based adhesives and is safe to use indoors or outdoors. The adhesive is good for use on fire pits up to 400°F (204°C). Flexlock Ultra Performance Concrete Adhesive permanently bonds together almost anything. It offers a broad service temperature range suitable for use in both hot and cold environments.