Last summer Granite Gear sent me an AquaTherm to gear test. The AquaTherm is a great product and I found two uses for it. It holds a 32 ounce/wide-mouthed Nalgene.
The first and most obvious use is to keep your drinks hot or cold. the AquaTherm will prevent your water from freezing in the winter and will keep your water cool in the summer.
The second use that I discovered was as a cozy for rehydrating meals. I simply put my dehydrated fare from home in the Nalgene and add the appropriate amount of boiling water. I pop it in the Aquatherm and my meal rehydrates and during fall trips is usually the perfect eating temperature when I am ready to transfer it to my bowl for eating.
I really like the design of this product. It did everything that the manufacturer claimed and was light enough to suit my needs.
I highly recommend this product as it is lightweight and practical. This is especially useful for those of us who backpack/camp in the winter months.