Made of durable insulating mylar material designed for space exploration, these emergency sleeping bags are lightweight, compact and have many uses. This is the same material used in the emergency blankets, except in sleeping bag form. Mylar can retain 90% of your body heat and can be used as ground cover or a shield from the elements. Not only can these be a life saver by providing warmth, but they can also be used as a ground cover, to build a shelter, collect rain water, and as a reflective signal device.. Dimensions: 84" x 36". Made of durable aluminized polyethylene.. Net Weight: 3.8 oz.