Originally Posted by
bajajoes

It would seem ANY metal ring would meet the definition!
And IF not then 3 separate rings woud be LEGAL!

Not really.
brass knuckles
pl.n. (used with a sing. or pl. verb)
A metal chain or a set of rings attached to a bar that can be fitted over the fingers to increase the impact of a blow with the fist.
The multiple rings need to be attached to a bar over the fingers. Yes, three separate rings are legal.
I agree it can be a silly distinction, at least visually.
There is a GREAT difference in getting hit with the attached variety and the separate rings. The illegal ones with the palm brace are the most dangerous.