Improved sunder

From DDO wiki

An Improved sunder attempt is a melee special attack that, when successful, results in a -5 AC penalty to the target for 24 seconds if it fails a DC 15 Fortitude save. Some creatures may be immune to the sunder effect..

It has a 15 second cooldown.^[unverified]

Prerequisites: Sunder, Power attack

A fighter may select this as one of his fighter bonus feats.