Moistop Ultra 10 is engineered to provide protection against moisture vapor migration through concrete slabs that can damage the integrity of the slab and structure above. It features a water vapor permeance of .02 perms and exceeds ASTM E-1745-97 Class “A”, “B”, and “C” requirements for under slab vapor retarders. With a 10 mil polyolefin film, it is puncture and tear-resistant.