SP, CN, RD ??? WHAT DO THESE MEAN?

[joe]

I often see these initial or shortforms on the more expensive and better rackets.

what do these symbols mean?

and whats the difference between them?

[Howard]

look it up in the search.I pretty sure no one wants to go through explaining it again

[Matt]

Well I can tell you two of the shortforms.
SP = Singapore
CN = China National team (<- CNs are supposingly better but you cannot really buy them in retail. I do know some places do but they are in the asian countries.).

RD, I have no idea.