Shield Material Expertise (Combat, Shield Mastery)Source Armor Master's Handbook pg. 19
You emphasize and exploit the potential of the special material from which your shield is made.
Prerequisites: Shield Focus, base attack bonus +6 or fighter level 4th.
Benefit: When wielding a shield made of one of the materials listed below, you can use the listed ability twice per day.
Darkwood: As a free action as part of an attack with your shield, you can drive splinters of your shield into your opponent, dealing an amount of bleed damage equal to 1 + the shield’s enhancement bonus.
Dragonhide: As an immediate action when you take energy damage of the type to which the dragonhide shield is immune, you can reduce the amount of damage you take by 10 hit points.
Living SteelUE: As a free action as part of an attack with your shield, you can attempt a sunder combat maneuver check against a metal weapon wielded by your target. If you succeed at the attempt, the weapon gains the broken condition; if the weapon already has the broken condition, it is destroyed.