Bests & Worsts Reviews from Amazon

Well, I saw the other reviews and decided to buy 5 of these for a trip to Hawaii with the family. I received them today and they weren't exactly what I had expected. The outside is a frosted clear plastic and the inside is a pure white hard plastic. Can't tell if they are molded together or just pushed into one another. They don't rotate so perhaps they are glued or fused in some way. There is a layer of air between them as well as what looks like a foil wrap or sock that has the words and coloring on it. The wrap is very loose fitting and looks rather cheap. However, I didn't want to loose hope so I decided to come up with a test to see how well the double walled bottle worked, since, after all it was getting good reviews. I decided to pit it against a standard squeeze bottle that people normally put on a bicycle, and one of those hard plastic, wide screw mouth bottles that people are always carrying around work. I put 10 ice cubes in each of the bottles and left them in a hot room (between 85 and 90 degrees). I didn't want the color to be a factor so they were not put in the sun. I waited until the hard plastic bottle's ice had melted by about 1/2 then I proceeded to measure the amount of water in each of the bottles. The hard plastic bottle had 11 teaspoons, the standard squeeze bottle had 8 teaspoons and the polar bottle had 4 teaspoons. So from this I think it's fair to say that the polar bottle was much better at keeping things cold than the others. The other thing I did was put a napkin under each of them. The polar bottle was the only one that didn't get wet underneath. The other bottles both sweated quite a bit. I think the double wall would not have stopped the sweating so the foil liner must be adding some benefit of some kind. The foil, by the way, does go around the bottom of the bottle as well, not just the sides. Overall, I think it will work out well and I am going to bring them on our trip. I hope this helps others in their decision.