the sound is really tinny on them, and you have to push kinda hard....the music skips cause they are moving the brush around. it's not real good on little teeth, jon has some trouble hearing it. but, we have found that if you take the brush and hold it still while just mashing it against your teeth, lol, you can hear the whole song without skipping
it's cool for younger kids, but i think my 11 year old would get tired of it pretty quickly, although i am gonna get her one