The first bivi bag to use Gore-Tex's air-perm Exchange Lite fabric, the Assault can be completely sealed up in foul weather and still allow a sufficient transfer of oxygen and carbon dioxide through the fabric (conventional bivi bags must be left partially open). In more pleasant conditions, the 200 degree entry and exit can either be used as a conventional digonal bivi, or hooked up to the branch of a tree and opened crocodile style. A built-in mosquito net keep insects at bay on summer evenings.