Your monastic training allows great precision with your quarterstaff. You can lash out swiftly and strike foes in vulnerable areas, stunning them.
This feat is taught and practiced by members of the Long Arm monastic tradition.
Prerequisites: Dex 13, Wis 13, Improved Unarmed Strike, Stunning Fist, Weapon Focus (quarterstaff).
Benefit: You can use your Stunning Fist feat with quarterstaff attacks.
Normal: You can use Stunning Fist only with unarmed attacks.
Source: Players Guide to Eberron p.109. Taken from Point of Infinity Forums.