You never see product quality like this for Guru Nanda's price, so to be honest I was skeptical at first. Plus the NATURAL whitening...I had my doubts. But I'm still amazed by how well these worked. And to paint the full picture, let me explain what these strips were up against. Ok I'm 38, smoker, daily coffee drinker, hadn't bleached my teeth since my early 20's. My teeth were YELLOW, y'all! I've spent the last 3 years traveling with my husband for his work so I haven't even had a cleaning sinc...