You are trained in how to properly use a tower shield.
Prerequisite: Shield Proficiency.
Benefit: When you use a tower shield, the shield’s armor check penalty only applies to Strength and Dexterity-based skills.
Normal: A character using a shield with which he is not proficient takes the shield’s armor check penalty on attack rolls and on all skill checks that involve moving, including Ride.
Special: Fighters automatically have Tower Shield Proficiency as a bonus feat. They need not select it.
Pathfinder RPG Core Rulebook. Copyright 2009, Paizo Publishing, LLC; Author: Jason Bulmahn, based on material by Jonathan Tweet, Monte Cook, and Skip Williams.