The Smile Science Harley Street Professional teeth whitening pen aims to make your teeth 8 up to shades whiter. Holds approximately 30 applications, no need to use trays or other whitening tools. The easy-to-use, stylish pen applicator brushes the whitening gel directly onto the tooth surface, helps removes stains in difficult areas around teeth and is great for touch ups or following a chair side or home whitening session. Just apply and Go! Comes in a sleek chrome finish. Clinically proven to provide up to 8 shades of whitening. Just apply to the teeth and go!