I have a bunch, what size are you looking for? They are kind of an odd shape/size don't work with every amp out there.
I'm looking for one for a Directed Audio amp. It's a big fat one, but the square plate isn't square. Well, it may be a square but the screw hole isn't centered in the square. This is what it looks like.
You can PM me if you prefer.
“The problem with socialism is that you eventually run out of other people's money.”
― Margaret Thatcher