Brass Knuckles Questions

[Adam Ormond]

Brass Knuckles reads:

Spoiler:

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. They allow you to deal lethal damage with unarmed attacks. 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). Monks are proficient with brass knuckles and can use their monk unarmed damage when fighting with them.

By RAW it would appear you can use Brass Knuckles to deal nonlethal damage without suffering a penalty. I'm not sure this is RAI, however.

Also, how does Disarm function with Brass Knuckles? Do you suffer a -4 penalty? What about if you're a Monk? Is it allowed to use only one of the Brass Knuckles so you could have a free hand to take the weapon?

[Scipion del Ferro]

If you are a monk you may deal nonlethal damage without taking a penalty. Anyone else would take a -4 penalty. Unarmed strikes usually do non-lethal damage, so if you took off the brass knuckles there would be no penalty. I'm under the impression these are the stats for just one set of brass knuckles, so one hand, leaving your other hand free.