Source Core Rulebook pg. 283
This weapon makes wide sweeping or spinning attacks, making it easier to attack multiple enemies. When you attack with this weapon, you gain a +1 circumstance bonus to your attack roll if you already attempted to attack a different target this turn using this weapon.

Monk Unarmed Attacks

Iron Sweep


Battle Axe, Dwarven War Axe, Falchion, Flail, Greataxe, Hatchet, Orc Necksplitter, Scimitar, War Flail