This bag is an excellent 3 season down bag for people who can take care of their gear. It is extremely lightweight and packs down to the size of a nalgene bottle. I've found it comfortable to a few degrees below freezing without wearing layers in the bag. It is made with lightweight materials, but after over a dozen backpacking trips, I have yet to see any tears or construction issues. The stretch system is awesome for those that sleep on their sides or move a lot in their sleep.