Colgate Optic White Light-Up 6% Hydrogen Peroxide is a Dentist Exclusive Take-Home Teeth Whitening Kit. Simple apply the serum with the precision brush onto your teeth. The LED device uses light energy to amplify the whitening power of the gel. The synergy between the formula and the device allows for brighter teeth when used for 10 minutes a day. To maximise results it is recommended to use after brushing and before bed. If sensitivity occurs, stop use.