A bed bags is a protective covering like a bag for a person to sleep in, comparable to a bed and blanket. The main idea behind a sleeping bag is to provide warmth and insulation. To a certain extent sleeping bag gives protection against wind, precipitation, and exposure to view. But as such you cannot use it in place of tent. To sleep on a sleeping pad is used as the sleeping bag does not provide ample cushioning. A bivouac sack is a waterproof cover for a sleeping bag and can be used in place of a tent for lightweight travelers or as a backup if stormy weather occurs.

Design types

A basic bed bags is simply a square blanket, with a zip stitched on three sides so that it can be folded in half and secured. A sleeping bag of this type is packed by being folded in half or thirds, rolled up, and bound with straps or cords. The basic design works well for most camping needs, but is not enough under more demanding conditions.

The second major type of sleeping bag, sometimes called a mummy bag due to its shape, is different in a number of important ways.

It decreases from the head end to the foot end so that it reduces its volume and surface area, and improves its overall heat preservation properties. A few of the bags are designed in such a way so as to accommodate women's body shapes.

It generally does not unzip all the way to the feet. The zipper is ineffectual in any sleeping bag's insulating qualities. Together with the tapered shape, this feature of this design helps protect the feet, which are more susceptible to heat loss than other parts of the body. It generally has a drawstring at the head side so as to help avoid the escape of warm air. But packing a mummy bag will not be so easy, as a mummy bag generally cannot be rolled like a rectangular bag. Instead, it is simply kept in a stuff sack or compression sack.

A bed bags should be filled with such a material that it is not too heavy and so different insulating materials are available for bed bags. Enthusiastic outdoorsmen usually prefer synthetic fill or down.

Synthetic fill does not absorb water, dries easily, and provides some warmth

even if it is thoroughly soaked. These characteristics may become very convenient if the sleeping bag is accidentally dropped into water on a cold day. Synthetic material is firm and resilient and insulates well even beneath a person's weight. Synthetic Fibers have the ability to loft faster than down which allows the bag to provide the insulation faster than a down bag.

The weight of down fill is less than synthetic fill and it also retains heat better, but is more expensive. Down

is useless if wet so should always be kept in a dry place as a soaked down sleeping bag may provide even less insulation than no sleeping bag at all, leading to hypothermia. Now the modern technically advanced bed bags often have water-resistant shells, so they can be used in damper conditions.

Other materials like cotton and wool have also been made use of for bed bags. Wool has the qualities of repelling water as it is naturally greasy and also resists compression, but the weight is the negative factor of wool. Cotton has the drawback of high water retention and considerable weight, but its low cost makes it a desirable option for uses like stationary camping where, these matters are of little consequence. Manufacturers of bed bags include:

Ajungilak, Big Agnes, Coleman, Fairydown, Hannah, Husky, Kelty, Macpac, Marmot, Mountain Hardwear, The North Face, PHD Mountain Software, Sierra Designs,Sir Joseph, Snugpak

The bed bags should be made of the world's pre-eminent synthetic insulation, to keep you warm in the most frigid and wet conditions on earth. If you are not worried about the weight of the sleeping bag but are worried about only wet, freezing weather condition you should choose your bag wisely. Overlapping shingle construction prevents cold spots from developing even after years of use. A soft, breathable silken lining feels nice to the touch and aids in heat transfer should it become a little too warm. A few of the newer bed bags offer larger alarm pocket with plenty of room for today's over-sized altimeter watches. A draft collar and full-length draft tube seal precious warmth in, while color-coded pull cords make for easy hood and chest adjustments. Generally they come with Nylon or mesh storage bag and stuff sack.

The modern bed bags keep you warm and comfortable down to 20ºF and a few of them weigh It makes them an excellent choice for cold weather camping. Nylon provides even construction for a more down proof fabric which makes sense that it is not likely to leak out of the bag. A silky smooth taffeta lining is soft on the skin and breathable for climate control inside the bag so you stay warm. A new design of the bags has unique split collar, which combines half of a down filled tube with flat fabric and cinches down to seal in heat as effectively as a full draft collar but without the excess weight.

A new design of synthetic bag ideal for expeditions in damp, sub-zero temperatures. In this bag you can sleep while resting your head on the built in pillow pocket you can stuff with clothes. A head level alarm clock pocket will not let you sleep late. A modern design of sleeping bag uses A-Flex construction to keep warm air from escaping and moisture from intruding. The fibers are silver treated and anti-microbial keeping your bag stink-free even if you sleep for many nights in it. Many other features like pillow, heater, and stash pockets and a draft tube are therein the bag. There are many bags, which are just perfect for summer surf trips, backpacking, and humid climates, which uses new type of insulation to keep protection from moisture while keeping you warm. There are many new advantages like getting stuff sack free and also a nylon mesh bag for long term storage, which helps preserve the insulation's loft. Generally all of them have features like t one-hand, color-coded pull cords to adjust the hood and easy-grab pull-tabs on the zipper. So enjoy camping.