The warforged's armor bonus is increased to +5, and the character is considered to be wearing light armor. He now has a +5 maximum Dexterity bonus to AC, an armor check penalty on all skill checks that armor check penalties apply to, and an arcane spell failure chance of 15%.
This feat must be taken at 1st level. Warforged who takes this feat cannot cast druid spells or use any of the druid's supernatural or spell-like class features. Warforged characters with this feat do not gain the benefit of any class feature prohibited to a character wearing heavy armor.
Without this feat, a warforged character has an armor bonus of +2.