The Mountain Lab Exhale Emergency Bivy Breathable Sleeping Bag is waterproof, windproof and-unlike most other emergency blankets and bivvies-is also breathable. This is a huge benefit for anyone who needs to hunker down and stay warm in cold conditions outdoors. The Mountain Lab Breathable Bivy is constructed of a four-ply material developed by NASA to breathe effectively yet still reflect 70-90% of a person&';s body heat. The advanced material is much stronger than a typical lightweight emergency bivy or blanket. The Breathable Bivy features waterproof seams, a 1/4 side zip for easy entry and a drawstring hood closure to help seal in the heat. Specifications: Length: 240 cm (94") Width: 75 cm (30") at the shoulders 55 cm (22") at the feet Weight: 190 g (6.7 oz) Packed Size: 16.5 cm (6.5") long x 10 cm (4") diameter