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.
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.
Some U.S. companies of backpacking sleeping bags have complied with the European Standard (EN 13537) technique of temperature level screening. Without entering into excessive deepness about exactly how they reach these numbers, generally they check the best sleeping bags under strict standards using a clothed dummy sporting long underwear and also a hat. Sensors on the mannequin document temperature readings.