Instruct: Classify an Amazon review as either positive or negative.
Query: overall this is among the best whitening products I've tried

I have used these for a while and I have seen results with them. They are easy to apply and usually stay on for the full time once they are applied. If the strips start to fall off (and that is rare) I just press them firmly back into place with a cotton swab and that usually does the job. I did take off one star because at times they can be somewhat painful because of the added pressure. Overall the Crest Strips are among the best whitening products I have used.