I tried this out recently hiking up Mt. LeConte in TN. The bag isn't the lightest made, but it stuffs down to a great size with the included compression sack and fit in my pack (Osprey Aether 70) easily. I used this in mid-30's temperatures and was very comfortable. The zippers are great. I had plenty of room in this bag, and I'm 6'3"/ 250lbs.