Needs review
Source: Player's Handbook

Description: You can bash with a shield while retaining its shield bonus to your Armor Class.

Prerequisites: Shield Proficiency

When you perform a shield bash, you may still apply the shield's shield bonus to your AC.

Special

A fighter may select Improved Shield Bash as one of his fighter bonus feats

Normal

Without this feat, a character who performs a shield bash loses the shield's shield bonus to AC until his or her next turn.