Waterstop® XP is an active polymer strip waterstop featuring XP technology that has been proven effective in a wide range of contaminated environments. The active polymer of Waterstop® XP is engineered to provide a consistent positive seal against concrete surfaces in fresh and high-saline ground water conditions. Waterstop® XP is effective in both continuous and intermittent hydrostatic conditions. The expansion and pliability of Waterstop® XP also provides effective crack-sealing and void-filling capacity.