You have survived many battles thanks to your skill with your shield.
Benefit When performing a shield bash, you deal 1 additional point of damage. Also, once per day on your turn as a free action, you may provide one adjacent ally a +2 trait bonus to his Armor Class. This bonus lasts for 1 round, so long as you and the target remain adjacent to one another. You can only use this ability if you are using a shield. You retain your shield bonus to your armor class when using this ability.
Pathfinder Player Companion: Humans of Golarion. © 2011, Paizo Publishing, LLC; Authors: James Jacobs, Colin McComb, Sean K Reynolds, Amber Scott, and Larry Wilhelm.