Ring of mind shielding doesn't work

[General Nuclear]

It's suppose to protect me against mind controll.

[Nordil(Hun)]

I think it only states you get an advantage roll agains charmed.
It does not grant you immunity. What it means you get 2 dices to roll a save against Charmed effect and take the better option. But ...with low wisdom saves it wont matter sadly if you roll bad for both.

I expected something useful from it, but realized it is quite useless compared to a +2 acid damage ring or a movement +2 ring.