| DM_Blake |
That is an "Armor" bonus.
You also get "Armor" bonus from chainmail, studded leather, full plate, etc. (all the armor you wear on your body). And also from the Mage Armor spell and from Bracers of Armor.
None of that stuff stacks with any of that other stuff since all of them are Armor bonuses.
So, to answer the title of the thread, no, they don't stack.
You can, however, stack it with a shield (or a Shield spell), and with a Ring of Protection and also with an Amulet of Natural Armor - you can have all of that stuff in place at the same time, along with your DEX bonus and your Dodge bonus if you take that feat.
Bah! Ninja'd by a t-rex? Didn't see that coming...
(then again, you never do, or they wouldn't have named it after ninjas)