Toughness
From AoP Wiki
Information
Toughness is a possible Perk you can learn during the leveling process of your character.
Perk Description
+5% (additive) Damage Resistance against all damage types.
Important notes
This adds +5% to each Damage Resistance in the game, at all times. Normal, Laser, Fire, Plasma, Electric and Explode.
This does not change your Damage Threshold in any way.