I bought these tights for the Sierra section of the PCT to give me a little extra warmth on the cold mornings at high altitude. These tights have completely lived up to my expectations and have provided comfort and warmth on 30-40 degree hikes plus the summit of Mt. Whitney with no complaints! When you put them on they feel fleece-like but when you get moving they breathe really well (no sweaty legs or overheating). I really like the drawstring waist too that allows you to adjust as needed. I'm an athletic build and tall so I ordered a large. It was a bit loose in the waist but the drawstring allows me to tighten it as needed. My only wishlist is that they were a little less bulky, but I gladly take the warmth and fit over thinner material. I also have gotten a lot of compliments on the reflective pattern of the design - it would be really great for evening outdoor running because of the reflection from light. Great tights for outdoor activities - backpacking, hiking, running, etc.!