Children under 3 use under adult supervision. Do not submerge in water, the unit can be damaged. Do not apply stickers to the narrow part of the brush, which would go into the mouth. Apply stickers to dry, clean brush, smoothing out any air bubbles. Allow to dry for 30 minutes, stickers are intended for permanent application to the toothbrush and are not reusable after application. Do not mix old and new batteries. Do not mix alkaline standard (carbon-zinc) or rechargeable (nickel-cadmium) batteries.