Your swim caps are perfect! I tell people all the time about them, my top reasons to buy them being: Keeps girls' hair out of their face, straps from goggles wont' get tangled in hair or pull on hair, keeps thin-haired people from getting burnt scalp, and MY KIDS ARE EASIER TO SPOT IN A CROWD OF BROWN HEADS BOBBING IN THE POOL!
(I think you should promote with these reasons as well!)