Uncanny Dodge

Uncanny dodge may be activated once per rest period to provide a 15 second boost of +4 to Armor Class and +4 to Reflex Saves.

This class feature is gained by Barbarians at 2nd level and by Rogues at 4th level.

Contrary to the manual, if a Barbarian or Rogue already has uncanny dodge from a different class he doesn't gain Improved Uncanny Dodge, but instead gains a second use of uncanny dodge. This was reported as a bug and is investigated.