Instruct: Classify Amazon reviews into positive or negative sentiment
Query: DO NOT BUY

We bought this item before going on a long trip. I figured that even though all the reviews were bad, it would be better than nothing. I was WRONG. We had the bottle in there for more than a half hour, and it was still cold. I took the bottle, and held it next to my skin for five minutes and it warmed up right away. So, if you have to choose between having nothing and buying this product, then choose nothing, and just use your body heat to warm it up.