I really enjoy using this product. I tend to use it primarily in the summer time to keep liquids cold while sitting in my car during long trail runs. It is really nice to know that a nalgene full of nice cold water and ice is sitting in the car while on the last mile of a run. I tend to have to share at least half a liter with friends whose water bottles water turned warm while sitting in the car for a few hours. They get really jealous about my ice cold water. This product is better than having to carry a bulky cooler or heavy thermos. I have used it in the winter during hikes and have never had my water freeze, but i honestly havent been in that cold of temperatures. Overall, great product. You wont be disappointed.

Size 1 fits the 1L nalgenes snuggly, better material that I thought it would be.

I'll keep it short and to the point. This OR Bottle Parka will keep your water from freezing, and that is all I ask for it to do. I have a #3 and a 1.5 liter Nalgene fits inside perfectly. The Zipper will freeze if you get it wet, and this will make it very difficult to open... Especially with gloves on, but with some effort it will open. Typical OR quality, you won't be dissapointed.

Performed exactly they way it was intended!
On a mount logan expedition it kept my water from freezing in minus 35 degree celciuis temperatures!