Talk:Irelia/@comment-141.237.137.216-20130121232556/@comment-4659726-20130122030319

No, Tenacity from items does not stack because they are named unique passives. (namely "Tenacity")

So getting a Zephyr/Merc's/Spirit of the ancient golem will not stack.

However a single tenacity item will stack with her passive and tenacity mastery in utility. multiplicatively of course.

0.65*0.6*0.85 = 33.15% duration of CC's. Average CC time is 1.5 sec which would mean it is now 0.5 sec. And that is assuming you have 3 champs in range for your passive. Still really good though.