Needs review
Source: Player's Handbook

Description: You have mastered the art of defense in combat.

Prerequisites: Combat Expertise, INT 13, Base Attack Bonus +6

When you use the Combat Expertise feat to improve your Armor Class, the number you subtract from your attack roll and add to your AC can be any number that does not exceed your base attack bonus.

Special

A fighter may select Improved Combat Expertise as one of his fighter bonus feats.

Normal

With Combat Expertise, the number can be no greater than +5.