"I figured out how to upgrade the brass knuckles to make every user of the toy a KO expert. I assure you I made one of those for myself and tested in real-life environment. Let the fact that I lived to write down this manual be the proof of the weapon's efficiency."
Found in Moresby in an abandoned market, on the ground beside a desk along the east wall. The market is at the large intersection south / south-west of the Warehouse.