I bought two of these for my first grandson a few years ago. Now his infant brother is going into the teething stage and made sure too buy him one too..Its a great alternative to those teethers you have to stick in the freezer and wait for them to refreeze. Its a gentle vibrating when baby bits down and the batteries are replaceable. IF this little one likes it, ill be buying a second one...definately something you want to have an extra of incase one gets lost