Wow, what an amazing pair of pants. Not only are they toasty warm (especially considering how thin they are), but the knit is so refined that I can wear these pants to work at the office as well as on a run. Amazing. I wish I could afford to buy 3 or 4 more pairs (and that they came in other colors) so that I wouldn't have to wear anything else. The waistband is super comfortable and stays exactly where you put it. I'm 5'6" and 128 pounds and the small felt like they were made just for me.