This professional whitening kit is the key to achieving a beautiful white smile. Lift those stains from coffee, wine, smoking, foods, and aging. Simply use the brush applicator to apply the whitening gel to the teeth and place the LED tray into your mouth. Connect the tray to your phone and turn on the light. Leave for 15-20 min and voila! Doing this process a few days a week will brighten your teeth in no time. * Very few people have sensitivity with this formula.