Cornugon Shield

Combat

You can use your spiked chain as both armor and weapon.

Prerequisite: Dex 15, Weapon Focus (spiked chain).

Benefit: When wielding a spiked chain, you gain a +1 shield bonus to your AC. When you are fighting defensively or using the total defense action, this shield bonus increases to +2.

Source: Cheliax, Empire of Devils