Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Does what it is supposed to do

I purchased this product to help with my allergies. I put it on my nightstand on the medium setting and I have been sleeping through the night better than I have in a long time. It has also eliminated the sinus issues I used to have every morning when I wake up.I do replace the refill pad daily but the refills are cheap and the results have been worth it. There is also something mentioned in the directions about reusing the pads by adding pure essential oils. This may be cheaper in the long run.