Ring of Invisibility

So I'm going to be using a ring of invisibility in my next game and was just curious as to how exactly the mechanincs of it work.

I'm assuming that I put the ring on and it automatically makes me invisible (+20/40 stealth +2 hit, no Dex on opponents armor all that good stuff) but does it stay on constantly? The spell itself says that when you attack you break your invisibility. However, this is not just a spell it is a persistent spell cast on a ring that is technically considered to be permanent right?

I guess the main question is, when I attack with my bow (my main weapon) will I be remaining invisible by doing so, will it make me visible for a few moments until I'm done attacking, or will it just simply break the spell and I will have to turn it on again in another round?

It takes a standard action to activate the ring.

In general if something doesn't list that it's a swift action or free action to activate it is a standard action.

So when you attack your invisibility drops (after the first attack). If you want to re up the invis then you have to spend a standard action on your next turn to do so.