Accuracy - This is the [Limit] for your attack rolls.
Unarmed attacks use the Physical [Limit] as Accuracy
Improvised weapons have an Accuracy of 4
Very Unwieldy objects as weapons have an Accuracy of 3
Armor - If the modified Damage Value (DV) of an attack causing Physical damage is less than the AP-modified armor rating, then the attack causes Stun damage instead of Physical damage.
Armor Penetration - Reduces the target's Armor rating for making damage resistance test.