Concentration on Hit
Increase your Concentration gain on hit by 2.
Where to get
Show on the tree It opens the Shadow tree, shown with the Gloom Stalker archetype.
It opens when any one of the nodes it needs has a point.
Numbers
Tree
Shadow
ShadowConcentration On Hit+2
What counts as a hit
On hit means a basic attack hit. Each melee swing restores Concentration once, on the first enemy it hits, and each ranged basic attack shot once when it lands. No spell restores it.
One hit restores Memory x 18 / 60, plus your Concentration On Hit. Concentration Regen bonuses raise the Memory part.
Concentration Boost
Plague Mind