Invisibility stealth bonus

What form of bonus does invisibility provide? In the spell I am finding no specification of this and so basically I'm trying to find out if it will stack with the bonus provided by having shadow armor.

Untyped bonus.

So as an untyped bonus does it stack with shadow?

Untyped bonuses stack, unless from the same source.

So, you could not get two different bonuses from being invisible, but the bonus would stack with everything else.

For support BBT is correct...shadow is a competence bonus so it stacks with anything that's not a competence bonus