The Bling Package Contains:Professional 22% Carbamide Peroxide Whitening Gel is the strongest at-home whitening gel made and is the result of decades of research. This highly viscous (sticky) gel is one of the few gels that has been reviewed and released for sale by the FDA. We use the highest quality ingredients and manufacturing processes available.Thermoform custom trays are made from a special polymer and are molded by heating the tray in warm water and then placing the tray in your mouth to form a precise mold of your teeth. One size fits all shapes and sizes of teeth because the bleaching tray will stretch or shrink during the molding process to provide your teeth with an exact fit.