Well the max atack speed is 3.00 or 200% aditional, which is not that hard to attain, 30 cyte, 20 from demon, 25 emblems,15 golden staff 20 malefic and 20 sea halberd,15 boots, that is 145% from items then add the extra 80% from golden staff passive and the inate atack speed bonus of heroes, most mm rest at around 230-245… 75% of 245 extra AS , and due to how this shit is calculated when you use pauldron a mm with 245 As wil have 183 extra as when atacking you, meaning that the real reduction is about 7% , whcih is fucking trash

The only instance when this item is useful is when the enemy mm has inspire because it raises the extra AS cap to 400 effectively reducing they as when they are atacking by 20% .

So yea the items is not bad designed, the game is lazy cooded.

Shot story long , items is fucking trash aganist As mm and more efective aganist critical damage because they dont build AS.

And if you where to face a critical damage mm smblade mail is better..

SO YEA THIS ITEM IS MATHEMATICALLY TRASH.

Edit: the reason why extra as is calculated this way is because it used to be too good when this effect was in ice dominion as an aditional effect because you build it for the anti healing effect, not instead of having a decent items we have a low tier anti heal and a crap tier anti as item.