According to other reviewers CVS fails the mark on teeth whitening products, this one no exception. I didn't realize when I purchased these, they were wax that's supposed to mold to your teeth, kind of like those wax teeth you get at Halloween. I way more prefer trays or strips. The upper wax molds fit okay but I had problems with the lower trays. My teeth are only slightly crooked on bottom and I had trouble getting them to stick. And I felt that no product was really coming into contact with my teeth. After 7 days, I feel that my teeth are no whiter than when I started. I got these on sale for $17.99 but they are usually $25.99. I would rather spend an extra $15 and get the Crest Advanced Seal strips which work much much better and way more comfortable. Plus you can always find a $7 off coupon on those.