You must go for a sleeping bag that is light, since you will be carrying it along with all of your gear. For some campers, this factor outweighs anything else like price or comfort. Synthetic materials are basically plastic threads. Usually the threads are hollow, reducing their weight and enabling them to trap more air. Synthetic filling material still insulates when wet. It dries quickly, is non-allergenic and less expensive. However as a disadvantage, such filling materials are bulkier, heavy and degrade over time. Goose-down insulation is offered in a few camping bags. It provides a more durable and compressible alternative to synthetic fill but features a slightly higher price tag. Down fill is great and modern synthetics cannot come even close in terms of warmth to weight and size ratio. However this comes at a cost. Down sleeping bags usually are of around twice the cost of comparably warm synthetic bags, but down bags can be half the bulk in most cases and about half of the weight. It is very efficient at trapping air and keeping you warm in the cold, and since down is also good at wicking moisture it is more comfortable than synthetic in the warm.
windsorjet made a real revolution in the industry.