Endless Healing Potion

Endless Healing Potion is a potion that restores 1500 to 2500 health. Using it does not consume it, and has the same cooldown as regular potions.

It is only usable by alchemists with skill 400.

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