In 1917 the zipper was developed and, of course, these made for a terrific seal for the rectangular sleeping bags allowing an individuals body warmth to remain trapped longer consequently keeping them warmer on those cold winter season evenings. Basically the term resting bag essentially suggests a safety bag for someone to rest in.
Remember that with time, from typical use, a treking sleeping bag will certainly lose its warming performance. This results from the fill obtaining a bit much more compressed. This will cause the "air pockets" to go away.
Draft Tube/Draft Flap: This is a flap or tube that leaves side the zipper. This flap helps reduce warmth loss. When choosing a treking rest bag, validate that the flap is simply sewn on the cellular lining as well as not with the bag. Make certain you analyze the zipper prior to purchasing to verify that the flap/tube doesn't problem or get captured in the zipper course. Fill: There are two fundamental options of bag fills; Fabricated (polyester) and Down (shielding feathers of ducks or geese).