I have an rei travel sack. I live in texas and I use mine allot all year long. Its allot like a poncho liner with zippers makes a good light bag, a good top quilt because the zipper runs allthe way down. a good bag liner to make your bag warmer and a good blanket. I like it allot. The closest other thing to it is a wiggys liner with zippers and that is way to expensive. I highly reccomend that you go for a rei travel sack.