Shield Wall

Whenever you are wielding a shield and are adjacent to an ally wielding a shield who also has this feat, the AC bonus from your shield increases, depending on the shield wielded by your ally. If your ally is wielding a buckler or a light shield, your shield bonus increases by +1. If your ally is wielding a heavy shield or a tower shield, your shield bonus increases by +2. You keep these bonuses even if your ally loses his shield bonus due to making a shield bash attack.