Healing Towers is a 
Vitality Gem. This Offense-type Gem can be slotted in the first slot of the Vitality attribute tree for a total 1,000 
Gold.
Slots 1, 2, 3, 4, and 5 are at nodes 1, 7, 13, 19, and 25, respectively.
How to obtain
Healing Towers can only be obtained through chests.
Notes
Healing Towers works when near enemy structures.