Unshaken in Iron

You know the precise limits of your armor, and trust it to save you from harm. You gain the armor specialization effect of light armor. If you are trained in medium or heavy armor, you gain the respective armor specialization effect for those armors as well. While in Tenacious Stance, you increase the value of your armor specialization effects by an amount equal to the value of your armor check penalty (adding +3 to the resistance while wearing plate armors, for example).