The following information may be of semi-spoilers if you have yet read the manga or watched the anime. All of the following information is based off of the manga version of Mermaid Melody Pichi Pichi Pitch unless stated otherwise. If you have not yet started this series, there may be spoilers. Please be aware.

The Aquamarine Pearl This is the source of Hanon's power; she needs it to transform into Aquamarine Pearl Voice.
Seashell Locket - Like the other mermaids, Hanon keeps her pearl in a seashell locket that she wears around her neck. Her locket is light blue in color.
Microphone - When she transforms into Aquamarine Pearl Voice, Hanon uses her microphone to project her singing voice.
Ariake-no-tsuki Orgel - This music box, a "treasure passed down by the Aquamarine Mermaids," allows Hanon to determine the whereabouts of any Aquamarine Mermaid in the world. Hanon uses the orgel to find the location of Meru's mother. It is Meru's mother who originally held the orgel in safekeeping, but she gave it to Meru in order to pass it on to Hanon. (Note: "Ariake-no-tsuki" refers to the moon that you can still see in an otherwise brightening sky, right before the sun rises.)
Key Rod -In chapter 20, Hanon recieves the magical Key Rod from Hippo. Ignoring the rod's magical powers, Hanon uses it like a baseball bat to break down a door within Gakuto's castle.

b a c k   .   c l e a r   .   f o r w a r d