Opalescence Go™ - Prefilled Teeth Whitening Trays with Potassium Fluoride - 15% Hydrogen Peroxide - Mint

In my opinion this is the best economically over the counter teeth whitening kit available. The slim teeth molds come prefilled with the perfect amount of gel in them. For my mouth the top mold was a little high which after several uses irritate d my gum line. I discovered I could trim a little from the top %26 the irritation stopped. I was whitening my teeth to match a crown that was being made for a front tooth, which was 1.5 shades from the most white. Don't recall the %23. Personally I had great results with using the molds 5 days on, 1 off, 2 on, 1 off, then used 2 more (9 total). For upkeep I use the molds once per week. For me these were the closest to the getting custom molds made %26 a higher % peroxide solution from the dentist

I first bought it at the dentist office and now I can buy online and use it 2-3 times a year. It really whiten your teeth in 3-5 days.