Unarmored AC bonus

Untyped armor bonus is a bonus to Armor Class resulting from a creature's innate ability to avoid unwanted contact in combat. Every creature has a base 10 points of untyped AC.

Untyped armor bonuses stack with themselves as well as all other bonuses to Armor Class and the highest source of one other enhancement bonus (such as the Barkskin spell).

Untyped armor bonuses are granted only by certain feats. These feats are either persistent or may be activated as a free action with an indefinite duration. This is in contrast to other AC types that may receive bonuses from multiple sources such as items, spells or feats with spell-like abilities, are often of limited duration and may require actions which take time to bring to effect. The known feats which grant bonuses to unyped armor are:
 * A Monk's AC bonus, Wisdom bonus and +1 per 5 levels.
 * Sacred Fist AC bonus: 1 at 1, 2 at 5, 3 at 10.
 * Small stature: +1
 * Combat Expertise: +3
 * Improved Combat Expertise: +6

Untyped armor bonus applies against all attacks, including touch attacks and while flat-footed.