Join the millions that have a whiter, healthier smile thanks to Watts Power White. Many will see a difference in as little as 1, 30 minute or less application... This gel is formulated to store in the refrigerator for touch ups for up to 2 1/2 years... Our Optimized Watts Power 35% Dental Quality Gel is used by Dental Professionals Worldwide. Sold in dental offices for Hundreds of dollars.. Whiten your teeth in half the time at home with this Watts Power professional strength formula. 4-9 Shades Whiter in less than 20 days, GUARANTEED. 30 minutes or less per application. See the difference after just on application. Formulated with 100-percent pure formula -- no fillers or additives used. Optimized pH formula for higher whitening performance and little or no sensitivity. Kosher USP glycerin (no animal by-products).