I looked for a long time for a water bottle insulating sleeve but most everything was not really all that great or the size would not work on my Contigo 18-20 oz bottle. Finally, I found this sleeve that had the measurements to fit the aforementioned Contigo bottle. As we so many things online, I was a little apprehensive on whether it would fit not only the height but also the girth around the bottle specially since the particular one I have is narrower at the bottom but wider at the top. It turned out to be a perfect fit. Better yet it actually does a true insulating job on keeping the water cold. I usually walk around 1.75 hours or 11 - 12k steps in the mornings In sunny and balmy Florida. The real test is that the water is not just cold but there is still ice in the bottle at the end of my walks. I dislike warm water from any container, with this sleeve I do not have any such issues. The sleeve comes with a sling which truth be told, it is not very useful, the Contigo bottle has a built-in 2 finger plastic loop which is how I carry the bottle. BTW, the bag in no way interferes with the plastic loop when opening the flip top to drink from the bottle. Yes, I am very happy with this insulator bag, it is well made and appears it will last for a good while.