You are skilled in using a shield, allowing you to gain greater defensive BENEFITS: from it.

Prerequisite: Proficiency with shields

Benefit: Choose one type of shield from the following list: buckler, heavy, or light. When using a shield of the appropriate type, you increase its shield bonus to AC by 1.

Special: You can take this feat more than once. Each time you select it, choose a different type of shield. A fighter can select Shield Specialization as one of his fighter bonus feats

Rulebook: Players handbook II (p. 82)

Ontrix brought up a good point. Why not with tower shields too? I agree with him and suggest that we add that to the list as a homebrew thing.

DO EET

I'm good with that.