Power Bangle

The Power Bangle is an item that is received by the players after they reach level 20 in Kingdom Hearts χ or the end of Quest 34: The Search for the Red Bandit Pt. 5 in Kingdom Hearts Union χ.

It allows the players to accumulate the Special Attack Bonus in Kingdom Hearts χ or enhance their medals's abilities with it in Kingdom Hearts Union χ respectively.

Kingdom Hearts Union χ
After their last battle, Chirithy approaches Player and compliments them on how strong they have gotten. It tells Player that it has something that will make them even stronger, and gifts them the power bangle, which they can now use to strengthen their medals by boosting them.

Briefly before the events of the Keyblade War, Player gets approached by Nightmare Chirithy, who tells them the true nature of the power bangle. According to Dark Chirithy, this entire time Player had been using the dark energy in the power bangle for their own uses. Chirithy insists that the power bangle was meant to collect dark energy and transform it into light, but Nightmare Chirithy refutes this by referring to its own existence as Player's darkness.