Unhindering Shield (Combat, Shield Mastery)Source Armor Master's Handbook pg. 19
You are accustomed to fighting with your shield.
Prerequisites: Shield Focus, base attack bonus +6 or fighter level 4th, proficiency with bucklers.
Benefit: You still gain a buckler’s bonus to AC even if you use your shield hand for some other purpose. When you wield a buckler, your shield hand is considered free for the purposes of casting spells, wielding weapons, and using any other abilities that require you to have a free hand or interact with your shield, such as the swashbuckler’s precise strike deed or the Weapon Finesse feat.
Special: A monk with this feat is not considered to be using a shield for the purposes of his AC bonus, fast movement, or flurry of blows.