A Mana Injector Kit is a device which can convert 20 into 20 . Each kit can be used one time. Patch 3.2.0 changed Runic Mana Potions, allowing them to stack to 20 normally, where previously they only stacked to 5. As this removed the advantage the potion injectors had previously provided, potion injectors were modified to grant an additional 25% benefit when used by Engineers.