Ring of Invisibility = Ring of greater Invisibility?

Riddle me this:
A caster has a ring of invisibility.
He casts magic missile and becomes visible.
as part as his move action he then takes off and puts back his ring.
Becomes invisible again.
Screw greater invisibility.

Problem?

Usually taking an item off is a move action, and putting an item on is a move action.

I don't have any problem with a character being able to re-activate a ring of invisibility with two consecutive move actions; does anyone else?

The ring is a standard action to activate.

Notice that there is no text anywhere about this ring activating simply by putting it on your finger, Frodo.

It is activated in the same manner as other rings, which is specified as a standard action.

Also, for what it's worth, it only lasts for three minutes per activation unless you pay more to customize it with a higher CL than the one in the core rulebook.

By activating this simple silver ring, the wearer can benefit from invisibility, as the spell.

Activating, not wearing. Magic item activation is a standard action.

EDIT: Curse you, 忍術!

Is there a ring of Greater Invisibility?

Edit: And I mean a non-custom ring. I am guessing there isn't one out of the book.

For the sake of argument, if taking off and on a ring can be done as one move. (accounting for the little distance traveled by the ring)
The caster could at best do:
*Round one* casts magic missile and becomes visible. move action on/off ring
*Round two* reactivates ring,+cast non offensive spell.
Total time spent visible: All the time of the bad guys attacks.
Which makes this manuver pretty useless.

any way to make it work ?
What if: 2rings 1cup, no no, 2rings 1 unseen servant.

*Round one* casts magic missile and becomes visible. precast Unseen does the switch (his move) and i activate as... still does not work.

You can't take the ring off and on to activate it...

As said above, the ring requires a Standard Action to use, which means you can't use the ring the same round you take another Standard Action.

Is there a ring of Greater Invisibility?

Edit: And I mean a non-custom ring. I am guessing there isn't one out of the book.

Not that I'm aware of.

That said, there is a rather interesting one in The Black Monastery. I just got around to reading that room last night, and even if I never run the module, I'm lifting that ring for future use.

Thank you all.
I forgotten about that pesky activation action.
A wiz had used it in a previous game and I wanted to prove/disprove it.
Still wish I could make it work.

Thank you all.

I forgotten about that pesky activation action.
A wiz had used it in a previous game and I wanted to prove/disprove it.
Still wish I could make it work.

Casting a Quickened spell will leave you with your standard action available to re-activate the ring. The balance being, Quickened spells will be in rather short supply.

Standing near cover...

1-Standard: Attack/cast spell and appear.
1-----Move: Duck behind cover (which may allow for a stealth check)

2-Standard: Activate ring.
2-----Move: Move out from behind cover.

Repeat...

. . . . . . . Or . . .

Round 1: Cast greater invisibility.

Why spend 20,000 gold, multiple turns worth of actions, and any appreciation the DM might have had about your personal character to cheese this when you're already a caster that can cast this spell?