The Melee Class can equip items into the additional weapon equipment slot with attributes that reduce traumatic damage by 50%. Traumatic damage is dealt only by certain types of attacks (generally they are slow, AoE attacks that can be dodged). The amount of damage dealt does not affect if an attack is considered traumatic. For instance, one enemy may have an traumatic attack that deals just 1,500 damage, while another enemy could have an attack that does 3,000 damage but is not considered traumatic.
Bugs: When traumatic damage is dealt to an absorption shield it is reduced, but the damage number displayed is not. If traumatic damage breaks through an absorption shield, the damage dealt to the shield is reduced, but the remaining damage dealt to health is not reduced.