Mana Potion Injector

Mana Potion Injector is a potion item that restores 1,800 to 3,000 mana (2,250 to 3,750 for engineers), and created in stacks of 20.

Source
This item is crafted with Engineering (345); taught by Schematic: Mana Potion Injector.

Disambiguation
There are two items with the name Mana Potion Injector, one with one charge, and one with twenty charges. Blizzard lists both in The Armory. The one with 20 charges lists no current source. Those should disappear from WoW as they are used up.

The flavor text on the old style Mana Potion Injector tooltip now reads:


 * "They just don't make 'em like this anymore..."

If you have an old style Mana Potion Injector or buy one from the auction house, be aware that they do not stack, but have 20 charges.