This is a really big concern for parents of babies or toddlers who are still putting things in their mouths. Obviously, the iPhone-shaped teething toy is meant to be put in the mouth and so is drool and waterproof. The only phones that are definitely water/ drool proof are the display phones with no working features. These phones lack internal components like batteries and microchips, so there’s nothing that can be destroyed, nor anything that can harm your baby or toddler. All other phones, including most of the play phones, have batterized features which will stop working if the phones are repeatedly exposed to moisture. Even if you remove the batteries, there are internal components that can act as contaminants, so you should keep these phones out of your child’s mouth as much as possible.