A 3.5 mil, high strength aluminum foil coated with an aggressive acrylic adhesive system. The foil conforms well to both fibrous and sheet metal ducts, providing an excellent vapor seal. The malleable foil also conforms well around corners and to irregular surfaces. Can be used under all weather conditions; designed for maximum adhesion over clean, dry surfaces, resists water vapor, odor and smoke transmission. For application ease, the adhesive is protected until the liner is removed. Measures 3 inches x 33 yards.