High-Barrier Foil Moisture Barrier Bags Built to MIL-PRF-131 and MIL-DTL-117
Military Packaging supplies barrier bags made to MIL-PRF-131, the military specification for watervaporproof, greaseproof foil barrier material. Built from a high-barrier foil laminate and constructed as heat-sealable moisture barrier bags, MIL-PRF-131 bags seal moisture-sensitive parts and electronics away from humidity for the long term. Order them on their own or built into a complete moisture barrier system we design around your equipment.
MIL-PRF-131 is the military specification for watervaporproof, greaseproof, flexible, heat-sealable barrier material. It defines the high-barrier foil laminate used to build the moisture barrier bags that preserve metal and electronic hardware.
The material combines a metal foil core with protective plastic films, which gives it an extremely low water vapor transmission rate, effectively a near-zero moisture barrier. Sealed with a desiccant inside, a MIL-PRF-131 bag holds a dry environment for years.
We supply bags built from MIL-PRF-131 material and constructed to MIL-DTL-117, so you get both the barrier the spec requires and the bag construction your program calls out. When a drawing calls for MIL-PRF-131, this is the bag it means.
Every MIL-PRF-131 bag we supply delivers the highest level of flexible moisture protection:
The specification defines what makes a compliant high-barrier bag material:
MIL-PRF-131 defines classes that set the level of barrier and flexibility. Class 1 is the high-barrier foil laminate most programs call out, built for the lowest moisture transmission and the longest preservation. The spec’s classes let you match the material to how demanding the storage and shipping conditions are.
We help you read the callout and supply the class your drawing requires, or recommend one when the choice is open. Send us the spec and the part, and we will confirm the right MIL-PRF-131 bag for the job.
MIL-PRF-131 bags protect the moisture-sensitive hardware across a defense shipment:
MIL-PRF-131 bags preserve the equipment these sectors ship, store, and depot every day:
A few factors point you to the right MIL-PRF-131 bag. Weigh these, or send us the part and we will recommend one:
A MIL-PRF-131 bag is the sealed core of a moisture barrier package. We wrap or cushion the part, place it in the bag with a desiccant and humidity indicator, and seal the foil laminate closed. From there, a box or crate carries the sealed pack to its destination.
Sourced as one system, the bag is matched to the desiccant, the wrap, and the container it ships in, so your equipment stays corrosion-free from the moment you seal the bag to the moment it is opened.
The barrier comes from the foil. MIL-PRF-131 laminates a continuous metal foil layer between plastic films, and that foil stops water vapor almost completely, where a plastic film alone would slowly let it pass. The result is a moisture transmission rate effectively at zero.
Sealed tight with a desiccant inside, the bag holds the interior humidity low and steady. Even as the outside climate shifts, the foil keeps vapor from migrating in, so condensation and corrosion never get the conditions they need to start.
It helps to know the difference between the two specs. MIL-PRF-131 governs the barrier material, the foil laminate itself, while MIL-DTL-117 governs the finished bag made from it, including the type, class, and style of the bag construction.
We supply both together: MIL-PRF-131 material formed into a MIL-DTL-117 bag. That way the barrier meets the material spec and the bag meets the construction spec, and your callout is satisfied on both counts.
MIL-PRF-131 bags are the barrier behind Method 50 preservation, the watervaporproof-with-desiccant method under MIL-STD-2073. Seal the part in the bag with the right quantity of desiccant, and the package holds the low humidity that Method 50 requires.
We size the desiccant to the bag and add a humidity indicator so your team can confirm the pack has stayed dry without opening it. Tell us the part and the storage, and we will build the Method 50 pack to spec.
Reading a barrier callout and building the right bag is what we do. Our team helps buyers and packaging engineers match the MIL-PRF-131 class and MIL-DTL-117 bag to the part, size the desiccant, and meet the preservation spec.
Send us the part, your storage timeline, and any spec callouts, and we will recommend the right MIL-PRF-131 bag and quote it, so your equipment stays dry from the first shipment.
Every program defines moisture protection a little differently, and we build to yours. When your documentation names a MIL-PRF-131 class, a bag construction, or a preservation method, we match it exactly. When the choice is open, we recommend the barrier that fits the part and the conditions.
That flexibility means your packaging satisfies the spec and keeps the contents dry in practice, with no gap between the two.
A MIL-PRF-131 bag does its best work as part of a full system. We wrap or cushion the part, seal it in the bag with a desiccant and humidity indicator, close it with preservation-grade tape, and enclose the pack in a box or crate rated for the journey. Sourced together, these layers carry your equipment dry and protected all the way to the shipping container.
We supply bags that meet MIL-PRF-131 for the barrier material and MIL-DTL-117 for the bag construction, and we build them into packaging that satisfies your spec. Where your drawing cites the material class or the bag type, we match it.
Where the drawing leaves a choice, we recommend the barrier and construction that best protect your equipment. Either way, you get moisture protection you can ship on.
Tell us what you are protecting, the size of the part, your storage timeline, and any spec callouts, and we will recommend the right MIL-PRF-131 bag and desiccant.
We supply MIL-PRF-131 bags on their own or as part of a complete moisture barrier system, with availability and turnaround confirmed in your quote.
We supply the highest-barrier bags built to MIL-PRF-131 and MIL-DTL-117, and we know how to build them into a compliant, sealed system.
That combination keeps metals corrosion-free, electronics reliable, and sensitive parts ready to use after shipping and long storage.
MIL-PRF-131 is the military specification for watervaporproof, greaseproof, flexible, heat-sealable barrier material. It defines the high-barrier foil laminate used to make moisture barrier bags, with a near-zero water vapor transmission rate for long-term preservation.
MIL-PRF-131 governs the barrier material, the foil laminate itself, while MIL-DTL-117 governs the finished bag made from it. We supply MIL-PRF-131 material formed into a MIL-DTL-117 bag, so both specs are satisfied.
Class 1 is the high-barrier foil laminate most programs call out, built for the lowest moisture transmission and the longest preservation. The spec’s classes let you match the barrier to your storage and shipping conditions. We confirm the class your drawing requires.
For Method 50 preservation and long-term protection, yes. The bag blocks vapor from entering, and a desiccant inside adsorbs any moisture already sealed in. We size the desiccant to the bag so the interior stays dry for the full storage period.
Yes. The material is heat-sealable and vacuum-ready. Vacuum sealing removes air before closing, which shrinks the pack, reduces trapped moisture, and holds the contents securely for shipping.
Yes. MIL-B-131 was the older designation for the same barrier material specification, now MIL-PRF-131. If your drawing still calls out MIL-B-131, we supply the current MIL-PRF-131 material to meet it.
Tell us what you are protecting and your storage timeline, and we will recommend the right MIL-PRF-131 bag and desiccant, then get you a quote.
