Does Armor Penetration Stack?

Hello, I was thinking of equipping the skill "Judge's Insight" on my Wammo, which gives him 20% armor penetration. However, I already have atrributes in strength, which gives armor penetration and other skills like Penetrating Chop. So, I was wondering if armor penetration can stack-- if not, I can safely reduce my atrribute points in strength.

I'm not sure but I can tell you one thing: the strength ap only happens when using skills.

I haven't tested it myself, but word is that the armor penetration from Penetrating Chop and similar attack skills does not stack, while most other forms of AP do stack.

So, strength armor penetration only applies for skills?

Sigh...

If the item/skill in question states that it adds armor penetration, such as "Armor penetration +10%" or "+20% armor penetration," then it adds onto whatever current AP you have. Examples are Sundering modifiers and Judge's Insight.

If the item/skill in question says that it "has 10% armor penetration" or something similar, then only the highest value counts. Examples are Penetrating Chop and similar skills, Hornbows, and the Strength attribute.

Thank you for clarifyign that, but now, my question is does the armor penetratio n granted by strength only apply for skills?

Yes; as the description of Strength says, it only applies when you use attack skills. And it doesn't stack with others.