Rectangle-shaped: These are specifically like the term recommends. A big rectangular shape. As a result of their form, they tend to be the least functional style of sleeping bag. There is a bargain of room within the bag for the body to warm up. Because of their heavy weight, they might be far much better matched for a "Automobile Camping" journey instead of a backpacking tour. They do have the benefit of a set of bags being able to be zipped collectively as well as come to be a resting bag for a couple rather than one person. With this style, a full or queen blow-up mattress beneath truly contributes to a pleasurable evening's sleep. (Once more not advised for the back country).
The last greatest factor to consider in selecting a bag is the insulation that is used in that bag. While both will do the work to maintain you warm, they both have their pros as well as cons. Some kind of extra padding under the bag is very advised.
It is very important to bear in mind though that the temperature rankings are overviews for recommendation only. Because, much like spicy food, consuming a jalapeno pepper for some isn't really a big deal ... but for others eating one would certainly seem like it would melt the skin straight off their tongue. The exact same goes with a sleeping bag. A +20 level rating would indicate that for most the bag would certainly be cozy sufficient. The most effective way to pick a cozy enough bag is to go with one that handles a 10 degree chillier weather condition than what you're anticipating to be sleeping in. Selecting in that manner needs to have you ... covered. (No pun planned.) And once more of course, appropriate sleep wear should fit the chillier or warmer demands you may have.