Improved Shield Bash

(Defenders of the Faith: A Guidebook to Clerics and Paladins, page 20, DnD 3.0)

[General]

You can push opponents back by bashing them with your shield.

Prerequisite

Power Attack

Benefit

Any shield bash you make with a small or large shield also affects your opponent as if you had performed a bull rush. You don't actually move into your opponent's square or incur attacks of opportunity for the bash. You also can't move your opponent back more than 5 feet, nor can you move along with the defender. You can't use this feat with a buckler.