Rectangular sleeping bags are the initial and also most typical form you'll see on the market. I directly don't think there is much of a visible difference in between the fillings nonetheless synthetic fibers will certainly not soak up water and will certainly keep you warmer also if the bag is a little bit wet. A damp down resting bag is very hard to dry out as well as is taken into consideration even worse than having no sleeping bag at all.
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.
There are primarily two types of sleeping bags. One is the mommy bag and the various other is the "traditional" rectangle-shaped resting bag. Currently mind you, ain't nothing incorrect with old school in any way. It might be your preference once you uncover just what it's like verses the mommy bag.