Instruct: Classify a given Amazon review into positive or negative sentiment.
Query: Great Product

I had carried tea or coffee to work every day in my old thermos, which was impossible to clean completely, so it picked up mildew and threw off the taste of everything I put in it.Then comes this little gem...I was amazed when I returned home from work to find that the tea from the morning was still hot enough to burn my tongue! Other than a burned tongue, I'm very happy with the performance of this thermos. You do need to prep the thermos by filling it with hot water beforehand, but it doesn't have to be boiling, mine never is. I fill mine with tea or coffee from a Keurig coffee maker (comes out at 192 deg F).