The barrier materials covered by this specification are intended for use in specialized military methods of preservation. The combination of all performance characteristics of MIL-PRF-131; seam strength and fabrication; water vapor transmission rate; breaking strength; puncture, blocking and curl resistance; contact corrosivity; delamination; and water resistance of markings provide the necessary requirements for protection from exposure to the extremes of the navy/naval aviation environment. Navy/naval aviation items are exposed to high moisture, high salt concentration, transfer at sea, rough handling, and minimal storage conditions. There are no commercial equivalents that meet the physical, mechanical, and corrosion requirements necessary to protect materiel that is exposed to the operational naval aviation environment. Specifically, Methods 41, 42, 43, 51, 52, and 53 of MIL-STD-2073-1 use MIL-PRF-131 as the premier source of barrier materials that provide water vapor proof (and water vapor proof with desiccant) protection for applicable items encountering the above conditions.