Sleeping Bags
Russian sleeping bag used in space station Mir and International Space Station basic sleeping bag is simply a square blanket, fitted with a zipper on one or two sides, allowing it to be folded in half and secured in this position. A sleeping bag of this type is packed by being folded in half or thirds, rolled up, and bound with straps or cords with cord locks. The basic design works well for most camping needs but is inadequate under more demanding circumstances.
The second major type of sleeping bag, sometimes called a mummy bag because of its shape, is different in a number of important ways. It tapers from the head end to the foot end, reducing its volume and surface area, and improving its overall heat retention properties. Some bags are designed specially to accommodate women's body shapes. Most mummy bags do not unzip all the way to the feet. The zipper is a weak point in any sleeping bag's insulating qualities. Together with the tapered shape, this design feature helps protect the feet, which are more vulnerable to heat loss than other parts of the body. Another design feature is a drawstring, equipped with a cord lock, at the head end to help prevent the escape of warm air. A mummy bag often cannot be rolled like a rectangular bag. Instead, it is simply stuffed into a stuff sack or compression sack.
The third type of sleeping bag is the sleeping bag with arms and legs, which provides ample flexibility and movement while sleeping. This type of sleeping bag is made for most overnight stays in tents, campers, boats, cars, huts, out hunting or fishing and other regular occasions. Using modern materials it reaches EN norm rated temperatures below zero degrees Celsius.