Shielded Caster

Whenever you are adjacent to an ally who also has this feat, you receive a +4 competence bonus on concentration checks. If your ally is wielding a buckler or a light shield, this bonus increases by +1. If your ally is wielding a heavy shield or a tower shield, this bonus increases by +2. Finally, if an enemy threatening you and your ally has the Disruptive feat, or another ability that increases the DC of concentration checks, the amount of the increase is halved.

Whenever you are adjacent to an ally who also has this feat, you receive a +4 competence bonus on concentration checks. If your ally is wielding a buckler or a light shield, this bonus increases by +1. If your ally is wielding a heavy shield or a tower shield, this bonus increases by +2. Finally, if an enemy threatening you and your ally has the Disruptive feat, or another ability that increases the DC of concentration checks, the amount of the increase is halved.