This sleeping bag is made from durable material that will stand up to the elements, keeping you warm and dry no matter what the conditions are outside. This SOS Bag is designed to keep you warm in even the coldest temperatures. They work by trapping your body heat inside the bag so you don’t lose heat to the colder air outside. This Sleeping Bag contains the same material used for NASA’s Space Blankets! This is not your ordinary sleeping bag. You will be using an exclusive HeatFlex mylar which is the same material chosen for different space blankets used by NASA for space explorations. Mylar is a type of plastic that is very thin. It is often used in space applications because it is lightweight and reflective, which helps to keep things cool. This bag is made from durable material that will stand up to the elements, keeping you warm and dry no matter what the conditions are outside.