Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Where the hey does one find a flat bottomed mug?

I ordered two of this item, so certain was I that this would do the trick for my coffee staying hot. It makes complete sense to me that it needs a flat bottomed mug in order to work efficiently and I never gave a thought when ordering that a flat bottomed mug would be so elusive!I have looked high and low. If anyone reading this review knows where I can locate such an animal, please let me know before I send this purchase back. Without the aforementioned flat bottomed mug, the product does a very poor job - so poor as to be useless!