This is, by far, the best water bottle I've found. For whatever reason, it keeps ice frozen a lot longer than any other bottle. For example, I fill it with ice cubes an hour or two before doing Bikram yoga and add water right before class starts. Even though the room is 110 degrees, there is often ice remaining 90 minutes later. No other water bottle comes close to keeping ice frozen that long under those conditions. I wish more people sold this.