crest strips,does it work?

just a quick note for anyone wondering about crest tooth whitening strips. i tried them while in america and have since bought them from ebay. my teeth were realy yellow and i debated paying the hundreds my dentist wanted to whiten them, but now i dont have tothe strips are realy easy to use and they realy work. ihave tried many other products on the market with no success, but be careful because there are many differnt strengths get a premium plus or more if you have a lot of yellowing. good luck