Combat Martial Arts [General]
Prerequisite: Base attack bonus +1.
Benefit: With an unarmed strike, the character deals lethal or nonlethal damage (the character’s choice) equal to 1d6 + the character’s Strength modifier. The character’s unarmed attacks count as armed, which means that opponents do not get attacks
  of opportunity when the character attacks them unarmed. The character may make attacks
  of opportunity against opponents who provoke such attacks.
Normal: Without this feat, a character deals only 1d3 points of nonlethal damage. Unarmed attacks normally provoke attacks
  of opportunity, and unarmed combatants cannot normally make attacks
  of opportunity.