Ok, so if it does what it says, (not like the fire shield -.-') then it should increase blocking ratio by certain percentage.
Let's say we have 16br shield and 6lvl passive, so the total br would be 16*1,06 = 16,96br. And I think this game has to round-down numbers like these, so it's still 16br
Or, maybe it just adds br? 16br + 6 from passive = 22? 22% chance of block, not bad, eh? That would be more likely, because that passive really does help, which wouldn't happen with 16.96br
So, does anyone know how it works?