These close combat weapons are designed to fit comfortably around the knuckles, narrowing the contact area and therefore magnifying the amount of force delivered by a punch.
Benefit: Brass knuckles allow you to deal lethal damage.
Drawback: You may hold, but not wield, a weapon or other object in a hand wearing brass knuckles. You may cast a spell with a somatic component while wearing brass knuckles if you make a concentration check (DC 10 + the level of the spell you’re casting).
Note: Monks are proficient with brass knuckles.
This reflects the most recent version of the brass knuckles, which differs from the version in the Advanced Player’s Guide.
Advanced Player’s Guide. Copyright 2010, Paizo Publishing, LLC; Author: Jason Bulmahn.