I knew I had to replace my very old custom-made plastic teeth whitening trays. I had used them for years with fair results. I happened to read a short paragraph about Snow in the Arizona State University bulletin about graduate students and their latest endeavors. I read about Snow, did the research and decided to purchase about a month ago. Thus far I'm delighted with the results. I began using the system immediately after receiving an outstanding cleaning by my hygienist. I drink 2 cups of strong coffee daily and ordinary brushing will not whiten my teeth. As recommended I've used the system daily for at least 3 weeks. If your teeth are dingy this will not be an overnight success story. Snow with daily use is brightening my smile and giving me fantastic results.