These bottles are all my family uses. To the other reviewers who have posted that this bottle leaches chemicals, I would ask that they do a little research before posting. First, you should wash the bottles in your dishwasher or hot water before using, this is just common sense and will remove any plastic odor (though I have never noticed any). These bottles are made from LDPE#4, which according to multiple studies, does NOT leach toxic chemicals into your water. On the other hand, Lexan, ie Polycarbonate ie Nalgene bottles have been shown to leach Bisphenol-A or BPA into water. You can feel safe buying and drinking from these bottles made of FDA approved LDPE#4. 5 stars

Normally, thermal bottles are too hard to squeeze to get fluid out of them, and they don't insulate very well at all. These are the first I've tried that actually worked, and they're just as squeezable as regular water bottles.

PROS and TESTIMONIAL: First time using these I froze them both, put them on the bike, went riding out in the heat of summer, and couldn't get a drop out of them because they remained frozen hard as bowling balls the more than two hours of that particular ride out on the open road. I finally had to open one and drink at least the one sip's worth of fluid that had melted. This was an absolute first. I've used other thermal water bottles over the years, but I tossed them all pretty quickly. None of them worked until these.

Second ride I refrigerated them and put ice cubes in before heading out. The ice melted but the contents remained fairly cool for hours or riding, again in the heat of summer.

Third time I came up with a brilliant idea. I filled them halfway and stuck them in the freezer, then filled them the rest of the way with refrigerated fluid just before heading out. This worked the best of the options I've tried so far.

One rider in my riding club had a great idea--freeze one bottle and fill the other one with fluid and ice. He says by the time he's ready for that second bottle it's melted enough that he can drink out of it. I go through two bottles in under three hours in the summertime, so I'm not sure this will work for me, but I plan to try it out on the next long ride.

In any case, they are absolutely freezer safe. Go ahead, fill them and freeze them, then see how long it takes before you can drink out of them.

FLAVOR: I've had absolutely no problem with the bottle affecting the flavor of the fluids I put in my bottles. Some have complained about this, but it seems more likely that they didn't thoroughly wash the bottles before use. There maybe some shipping wax in there, or just some residue from the manufacturing process. Just two drops of dish soap; any more will have your fluids tasting soapy for several rides; wash out those bottles good even before the first use, and you wont have a problem.

CON--a techical problem and recommendation: Before you order two of these bottles, make sure they will actually fit on your bike. One on the downtube definitely will, but you might have to go with one of the smaller ones for the upright cage mounted on your seat tube because it wont fit under the top tube. Mine just barely clears the top tube when inserted in the upright cage on my 54cm Trek frame; if my frame were only 2cm smaller, I imagine it might not fit.

I've seen several riders with a 24oz on the downtube and a smaller one on the upright, but the only problem there is grabbing and reinserting the bottle in the upright cage while riding. Personally, I used up the one on the downtube and them switch them.

In any case, if you have even the slightest doubt about that second bottle fitting, buy one, see if it fits, and if it does then order a second one.

BOTTOM LINE: If they were normal water bottles I would buy them just for the size. Having 48oz of water on you without having to wear a Camelbak is nice.

The fact that the thermal technology works in this make and model is just miraculous, as I've tried several thermal bottles before and none of them seemed to do a damn thing to keep cold liquids cold and hot liquids hot--in the winter.

And lastly, every other thermal bottle I've tried was difficult to impossible to squeeze one handed while riding, so they were too inconvenient to be useful on a bike ride. Especially on a road ride near a major city, it's tough to get those precious seconds for a quick drink, so it really needs to work--and these do. 5 stars

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. 4 stars

We have found these water bottles extremely useful. They keep beverages cold for several hours and avoid the "sweating" that is often a problem on humid days. 5 stars

This bottle leaches the chemicals from which it is made into the contents of the bottle. By the time I finish a two hour bicycle ride, any water that I might still have in the bottle smells more like a superfund cleanup site than an opportunity for refreshment.

I lost the lid just today on a ride, and was actually relieved because now I don't have to choose between the toxic taste that this bottle created and wasting the money on a bottle I have only had for a few weeks.

As far as the thermal aspect of this product, it added a bit to the length of time my water was kept cold (I start with filtered/refrigerated water). Don't by any means expect a thermos here.

Also, it never really fit properly into my water bottle cage on
my bicycle. Whether this is a bottle unusually stout, or a cage unusually narrow I cannot say, but I always had to press a bit to make it fit.

Bottom line: Does it really matter how cold your water is, if it is all the while absorbing a nasty chemical taste (IE: molecules) from the plastic which holds it?

Every time I took a drink out of this thing, for some reason I kept thinking about Chinese toys. 1 star