The GORE-TEX® laminate for sleeping systems is GAS PERMEABLE.

GORE-TEX_graphic1-03-01Top Material:

GORE-TEX_graphic1-03-01All our Bivy Bags and Bivy Tents have the revolutionary gas permeable laminate as their topmaterial. The material is absolutely waterproof, windproof and vapour permeable – the well-known properties of laminates. What’s new is that the new laminate is also gas permeable. That means that the Bivy Bag can be closed completely without having to keep a ventilation slit open for fresh air. The fresh air permeates through the material itself.
The benefits are obvious:

Bottom Material:

Highly water-proof and cold-flex durable laminate.

Does „Gas-Permeability“ work under extreme rain fall conditions? Raintower testing of gas permeable, completely closed Bivy Bags – O2 concentration inside head area