Our Boots Expert Teeth Whitening Kit with blue light activation can whiten your teeth by up to 10 shades in just 1 week and gets to work immediately. Even better, the silicone mouth tray is soft and flexible, giving a super comfortable fit which you will find more gentle on your gums. Directions: 1. Clean your teeth as you normally would.2. Charge the mouth tray by placing it under any type of strong light source e.g. phone torch, lamp, or sunlight.3. Gently squeeze the Pretreatment tube until the sponge tip is covered, use the sponge tip to cover the front of your teeth.4. Apply a thin layer of whitening gel into the mouth tray.5. Fold the mouth tray gently in your hand and place in your mouth for 15 minutes, but no longer than 20 minutes.6. Remove tray and rinse mouth with water. Clean tray with water after use. Ingredients: Whitening Gel: Glycerin, Propylene Glycol, Carbomer, Potassium Acesulfame, Mica, Triethanolamine, Menthol, Sodium Carbonate Peroxide, Cl 77891.Pretreatment Gel: Aqua, Glycerin, Alcohol Denat, Sodium Lauryl Sulfate, Cellulose Gum, Poloxamer 188, Poloxamer 407, Aroma, Sodium Citrate, Caffeine, Methol, Polysorbate 20, Potassium Acesulfame, Sodium Benzoate, Sodium Saccharin, Sucralose, Cl 42090.