When can we have a %tank item.

I've been doing some math, yes I know this is a dangerous thing to do, but what if we had an item that gave no base stats, and only gave 18% bonus to all HP, Magic Resist, and Armor and Cost 2.8k gold.

The Item would become gold efficient at 3 tank items + the new item. Meaning that yes bruisers could use the item as a 4th item (but only at 100% gold efficiency). More importantly true tanks that invest into 4 tank items +the new item could use the item at 118% efficiency. The 118% gold efficiency assumes base stats with, ,,,.

In pretty much the most abusive case of 4 and 's base stats it would be 126% efficient.

This does however assume that boots, runes and masteries are negligible, all of these however do have the potential to increase the items efficiency. With Full MR and AR runes or with full hp/level runes, it increases the items efficiency by 12%.

Edit: Just to note, on with ,,,, it is 1.12% efficient. With ,,, it is 98.9% efficient. With , it is 84% efficient.

Just remember it also takes up an item slot, so 4 items+ this item + boots would make a full build.