Originally Posted by
Kelrugem
That is something different :) Rings do not provide enhancement bonus to armor (at least I have never seen such a ring, though homebrew might allow that of course)
Magical natural armor is treated as enhancing the existing natural armor, so, it stacks with the natural/native natural armor :) But different sources of magical natural armor do not stack :) so, strictly spoken there are two types of natural armor, natural and natural enhancement. I do not think that bmos meant the latter because enhancement bonus is again something different :) (and only armor, weapons and shields have the enhancement bonus as far as I am aware of)