Mikeg,
The rollerplates are stainless steel plates which are included in the Symposium Rollerblock set. It allows you to place these smooth surfaced plates between your component and the ball bearings, should you find the underside of your component lacking the smooth texture that is required, for the proper movement of these ball bearings.
Unfortunately, I can't tell you where, but I do remember reading somewhere, that the Rollerblocks do deal better with larger/stiffer cords than the Aurious do.
I am thinking about returning the Rollerblocks that I've purchased since I find my CDP sounding better without them.