Originally developed for the military this foil like material (available in varying weights & strengths) is used in conjunction with an air evacuation system to create a secure atmosphere within your crate.
Desiccants (Silicajell) packets are placed inside the barrier bag to absorb any moisture in the remaining atmosphere.
V.C.I. (Volatile Corrosive Inhibitor) Pads and/or VCI poly wrap of your equipment within the barrier bag complete a controlled atmosphere for maximum protection.
Humidity plugs and humidity indicators are also installed within the barrier bag. There are view points in the vac bags so you can monitor the inteior of the bag.