Another stroke of genius I didn't think of that's too good not to share. This has been one of the hottest summers on record and I find myself keeping a small bottle of water in my car. I never found this necessary before, thinking that I could make it from place to place without food and drink. Most of my stops are less than half an hour apart. However ... here's the genius part ... fill your water bottle half full and keep it in your freezer. Fill it the rest of the way when you are ready to go. You'll have cold water for much longer. No extra charge. You're welcome!