well my source is a us policeman on another forum.
they are also one of the proscribed items you're not supposed to buy mail order for delivery into the united kingdom.

Anyway I don't need brass knuckles I have bear paws :-)
http://www.amazon.co.uk/Homdox%C2%AE...ords=bear+paws

and yes they are legal - the world is mad :-)

Mnd you I've only used mine for pulling pork - so far ;-)