Crux B1 Scout bivi-bag Bivvy Bag A glorified sleeping bag cover, the B1 Scout is as simple as a bivi bag gets. It has a drawcord around the face, but you can never completely seal the face area and there is no mesh insect screen. The design may be plain, but the B1 Scout\'s X-tex fabric is decidedly hi-tech. X-tex fabric has a woven textile face with a coating to make it both waterproof and breathable, with a 50 denier polyester face. Most bivi bags use a fabric with a microporous membrane or coating. These rely on differences in the partial pressure of humidity in the air in order to breathe. They only work however, when the humidity is in the vapour state: once condensation has occurred they cease to breathe. X-tex fabric is different and it is able to absorb water even in the liquid state and still continue to breathe. Features Simple lightweight design Small pack size Waterproof & Breathable X-tex fabric Sizes: Regular (M) and Long (L) - The Long (L) version is approx 10cm wider and longer than the Regular (M) Technical Specification Regular Size Weight: 386g + 10g stuff sack Long Size Weight: 440g + 10g stuff sack Hydrostatic head: 20,000mm MVTR: 25,000g/m2/24hrs Regular Size Inside length: 204cm Regular Size Width at shoulders: 68cm Regular Size Width at footbox: 49cm Long Size Inside length: 214cm Long Size Width at shoulders: 78cm LongSize Width at footbox: 59cm