Items available to facilitate 45 percent armor pen: 
Items available to facilitate 45 percent magic pen:
Oh just kidding, you are only allowed to have 35 percent, here, have this item that we boosted the price way up on over the last season and nerfed it's penetration percentage instead of being fair and making it similar to this item 
,which gets 35 percent armor penetration by the way, {don't tell them they pay double for the same amount of pen}
Anyways, here you go: 
ModWulf Helhammer1 votesOh look, someone who completely ignored the fact that Last whisper is BONUS armor pen, whereas Void staff is TOTAL magic pen
Chaos Milk Tea1 votesYeah, like the other guy said: Void staff is generally stronger.
Unlucky471 votesEven if void staff is total magic pen, you can't ignore the fact that Black Cleaver exist as an item, and that's total armor pen for the same as void staff. So if you build both, that's around like 60 - 70 % of armor gone. Why can ad champions blow up tanks and bruisers but ap champions can't?
