Endless Mana Potion

Endless Mana Potion is a potion that restores 1800 to 3000 mana. Using it does not consume it, and it has the normal potion cooldown. It is only usable by alchemists with skill 410.

Source
This item can be crafted using Alchemy (410); taught by any Grand Master Alchemist trainer in Wrath of the Lich King.