Rectangle-shaped sleeping bags go as much back as the late 1800's when a mail order catalog pioneer Pryce Pryce-Jones came up with the suggestion to attach 2 rectangular carpets together with ties. He is taken into consideration to be the innovator of today's contemporary rectangular sleeping bag design. After the war he had several of these bags still left as well as made a decision to market them to the public.
If you see a +20 degree score that would certainly indicate that the bag should be cozy enough for temperatures that are 20 levels or warmer.. And if you see a - 20 level score then it has actually been figured out that the bag needs to be cozy sufficient for minus 20 degree climate.
The other sacrifice is the size or thickness of the bag. A mummy sleeping bag essentially will certainly be much smaller sized for bring around which is why it is a preference for many backpackers/hikers. The rectangular resting bag isn't as small yet because it's not common to be lugging it, apart from somewhere in a vehicle while getting to your intended location, the bulkiness of the bag is not as large a problem.
Rectangle-shaped shaped bags are one of the most popular and also most acquainted. These supply you with even more space for movement within, lowering that claustrophobic feel to some degree. Since they are of a square form they could also be whized to a 2nd to generate a double sized resting bag, huge enough for two individuals to sleep in. Or, if you completely do not like the feeling of being zipped up, you can leave the bag unzipped completely and also utilize it as a blanket rather. These bags are typically rather huge, and also might not be perfect for treking trips as they can be instead bulky and unpleasant to carry.