I have bought and used many water bottle cases over the years. This, I regret to say, is not a good one. The insulation is minimal and I think it probably has the worst zipper around! I bought two and both zippers got destroyed just with regular use. As of late I purchased one from Camping Gas and without a doubt is the best so far although slightly more expensive. Don't worry it's worth it!

When you have water from the previous night in the freezer, it keeps it cool from morning until noon.

Serious construction, it is a very good case. From the morning when I put the bottle in to take it with me until 3 to 4 o'clock it is cold, from there on it takes the temperature of the environment.

It holds the temperature extremely well in a 1.5L bottle. 4 stars because I haven't tested it in extreme heat directly under the sun yet. I will come back