This self-sealing, non-swelling preformed joint sealant provides a lasting, watertight bond on both fresh and cured concrete surfaces. Synko-Flex® Waterstop achieves a watertight seal within cold joints at footings, walls and slabs. Rain and moisture resistant, Synko-Flex® Waterstop is also a simple, long-term solution for sealing pipes, sleeves, and collars embedded or cast into concrete structures.