I've had nothing but a pleasant experience with this duo. It is easy-to-use and delivered as promised, within 3days of use I could already see a difference. My teeth was whiter and brighter. The products are gentle yet effective and delivered dentist-level results quicker than any other whitening product I've tried. I have very sensitive teeth and did not experience any tooth sensitivity from the products, they are completely enamel-safe and an absolute game-changer. I will definitely be repurchasing this duo and have gotten friends and family on it too. I highly recommend these products for quick, easy and safe whitening results as you sleep.