I see that a few people complained that these dolphins don't work the way they planned.  That may be so but my kids (3 and 5) LOVE them!  They make up their own things to do with them and even make sure to pack a couple when we go on trips.  They use them for pouring experiments and the love to match the colors together.  The whistles, really, haven't gotten much use in the five years we've had them but both kids do know how to drain the water out of them if they want them to whistle.  They are a must-have in our house and I am buying some for our new nephew born yesterday.  All other have come and gone.  But the dolphins are still here - which is testimony enough for me.