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.
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).