In both shows, each of the girls have a special type of friendship jewelry. Mako mermaids have rings, and the H2o mermaids have necklaces.
They are all so pretty! The first picture is all of the H2o mermaids in season one and two holding their necklaces. The second is of Cleo from H2o wearing the necklace they get in season three. The third one is of Nixie from Mako mermaids holding her mood ring. It would be so cool to have pretty matching jewelry with your best friends. :)