What it is:Once you own your GLO Device, simply purchase an additional GLO Brilliant(TM) Mouthpiece and Case for each member in your home, remember you can share the same GLO(TM) Control.What it does:The GLO Brilliant Mouthpiece builds Guided Light Optics Technology directly into its design and is the key to the GLO innovation. The mouthpiece contains a molded flexible circuit with activating light and heat that, when placed into your mouth, accelerates the GLO Whitening Gel on your teeth. This process creates greater efficacy and speeds up whitening results without tooth sensitivity. The GLO Mouthpiece seals the system, preventing whitening oxygens from escaping the surface of the teeth. As it warms up, it form fits to your mouth, whitening the top and bottom teeth from the front and back. By purchasing additional GLO Brilliant(TM) Mouthpieces, you are able to share the GLO Brilliant(TM) Personal Teeth Whitening Device with an additional person in your household. Make it a 'his and hers,' or a 'yours and mine.'What else you need to know:The GLO Brilliant(TM) Mouthpiece requires the GLO Brilliant(TM) Personal Teeth Whitening Device for operation.