There is a Legacy version here.


Source GM Core pg. 270
When you Invest an Item that has the apex trait, it improves one of your attributes, either increasing the attribute’s modifier by 1 or to a total of +4, whichever would give you a higher score. This gives you all the benefits of the new attribute modifier until the investiture runs out: increasing Intelligence lets you become trained in an additional skill and learn a new language, increasing Constitution gives you more Hit Points, and so on.

An apex item grants this benefit only the first time it’s invested within a 24-hour period, and you can benefit from only one apex item at a time. If you attempt to invest an apex item when you already have one invested, you don’t gain the attribute modifier increase, though you do gain any other effects of Investing the Item.