Made from state-of-the-art resins, VaporBlockPlus is an underslab retarder and barrier that offers excellent impact strength, while a low perm rating impedes water vapor and naturally occurring gases from travelling upward through a concrete slab or a concrete wall. It meets all requirements of ASTM E-1745, Class A, B, and C, and is available in 20-mil. roll, measuring 10 ft. wide and 150 ft. long. Raven Industries. 800-635-3456.