This bag was used on one trip and kept me toasty while hiking Mt. Kenya and Kilimanjaro. Synthetic fill and mummy shaped, the bag is rated at zero degrees. Lots of technical features including a great hood. Stored in well ventilated spot in large storage sack to keep the fill loft high. No tears, zipper problems, musty smells, etc. If you need a warm bag for winter trips, this is it. Includes storage bag and a good compression sack.