Semi-Rectangular: I call this the cross. This backpacking bag is rectangle-shaped ahead and afterwards slenders along towards the feet. With this type, you obtain added space, but not as much weight as a true rectangular resting bag. For those who are claustrophobic, like me; we can reach sleep a little better inside a bag with added room in it and still have some benefit from the form.
An additional kind of sleeping bag is the mommy bag. Unless you are intending a trip to an extremely cold climate and resting outdoors after that you will possibly be happier with rectangular sleeping bags over a mommy style bag. These bags have a certain use as well as they are extremely particular, extremely cool weather condition, mommy sleeping bag.
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.